Computing only Prime Powers with NestList












3












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Is there a simple way to compute only prime powers of a function f with NestList? That is, I want to compute:



{f[x_0], f^2[x_0]=f[f[x_0]], f^3[x_0], f^5[x_0]...}


up to some specified prime power. Thanks so much!










share|improve this question









$endgroup$

















    3












    $begingroup$


    Is there a simple way to compute only prime powers of a function f with NestList? That is, I want to compute:



    {f[x_0], f^2[x_0]=f[f[x_0]], f^3[x_0], f^5[x_0]...}


    up to some specified prime power. Thanks so much!










    share|improve this question









    $endgroup$















      3












      3








      3





      $begingroup$


      Is there a simple way to compute only prime powers of a function f with NestList? That is, I want to compute:



      {f[x_0], f^2[x_0]=f[f[x_0]], f^3[x_0], f^5[x_0]...}


      up to some specified prime power. Thanks so much!










      share|improve this question









      $endgroup$




      Is there a simple way to compute only prime powers of a function f with NestList? That is, I want to compute:



      {f[x_0], f^2[x_0]=f[f[x_0]], f^3[x_0], f^5[x_0]...}


      up to some specified prime power. Thanks so much!







      recursion






      share|improve this question













      share|improve this question











      share|improve this question




      share|improve this question










      asked 7 hours ago









      user413587user413587

      725




      725






















          7 Answers
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          $begingroup$

          Lets say you have f(x) and you want results up to 10



          n=10;    
          NestList[f,x,n][[#+1]]&/@Prime[Range@PrimePi@n]



          {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]]}







          share|improve this answer











          $endgroup$





















            2












            $begingroup$

            Here's a way using Compose:



            n = 10; ComposeList[ConstantArray[f, n], f[x]][[#]] & /@ Prime[Range@PrimePi@n]

            {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]]}





            share|improve this answer









            $endgroup$





















              2












              $begingroup$

              Here's a way to accumulate the nestings, i.e. use the previous nesting as the starting point for the next one:



              primeNest[f_, x_, n_] := FoldList[Nest[f, ##] &, f[f[x]], Differences[Prime[Range[n]]]]

              primeNest[f, x, 5]



              {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], 
              f[f[f[f[f[f[f[x]]]]]]], f[f[f[f[f[f[f[f[f[f[f[x]]]]]]]]]]]}



              (Depth /@ primeNest[f, x, 20]) - 1



              {2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71}






              share|improve this answer









              $endgroup$





















                1












                $begingroup$

                One can in fact use NestWhile along with NestList, in the same spirit as this previous answer:



                NestList[NestWhile[f, f[#], ! PrimeQ[Depth[#] - 1] &] &, x, 5]
                {x, f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]],
                f[f[f[f[f[f[f[f[f[f[f[x]]]]]]]]]]]}


                Here is another variation which yields the same result:



                NestList[Nest[f, #, NextPrime[Depth[#] - 1] - Depth[#] + 1] &, x, 5]





                share|improve this answer









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                  0












                  $begingroup$

                  This may not be an elegant and smart way to do it but here is one way.



                    exp = NestList[g, x, 12];
                  selector = PrimeQ[LeafCount /@ exp - 1];
                  Pick[exp, selector] /. {g -> f, x -> x0}



                  {f[f[x0]], f[f[f[x0]]], f[f[f[f[f[x0]]]]], f[f[f[f[f[f[f[x0]]]]]]],
                  f[f[f[f[f[f[f[f[f[f[f[x0]]]]]]]]]]]}







                  share|improve this answer











                  $endgroup$





















                    0












                    $begingroup$

                    Well, maybe not as elegant as with NestList, but for the first five primes (n=5), for example, here is another way



                    n = 5;
                    ls = {};
                    For [k = 0, k < n, k++,
                    (
                    Q = f[x];
                    For [j = 1, j < Prime[k + 1], j++,
                    Q = Map[f, Q];
                    ];
                    ls = Join[ls, {Q}]
                    )
                    ]
                    Print[ls]


                    Here is the result:



                    {f[f[x]],f[f[f[x]]],f[f[f[f[f[x]]]]],f[f[f[f[f[f[f[x]]]]]]],f[f[f[f[f[f[f[f[f[f[f[x]]]]]]]]]]]}





                    share|improve this answer










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                    mjw is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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                    • 1




                      $begingroup$
                      Why should I avoid the For loop in Mathematica?
                      $endgroup$
                      – corey979
                      6 hours ago










                    • $begingroup$
                      Yes, I've seen that! And I've got two loops! If n>10^4, great point! But for n=5 or n=10, do we care?, this code ran pretty quickly.
                      $endgroup$
                      – mjw
                      5 hours ago












                    • $begingroup$
                      Thank you for the tip, here it is with For replaced by Do: n = 5; ls = {}; Do [ ( Q = f[x]; Do [Q = Map[f, Q], {j, Range[Prime[k] - 1]}]; ls = Join[ls, {Q}] ), {k, Range[n]}] Print[ls]
                      $endgroup$
                      – mjw
                      5 hours ago





















                    0












                    $begingroup$

                    ClearAll[primesNest0]
                    primesNest0[f_, x_, n_] := Nest[f, x, #] & /@ Prime[Range@PrimePi@n]
                    primesNest0[f, x, 10]



                    {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]]}




                    Also



                    ClearAll[primesNest1]
                    primesNest1[f_, x_, n_] := Fold[#2@# &, x, ConstantArray[f, #]] & /@ Prime[Range@PrimePi@n]

                    primesNest1[f, x, 10]



                    {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]]}




                    and



                    ClearAll[primesNest2]
                    primesNest2[f_, x_, n_] := Compose[##&@@ConstantArray[f, #], x] & /@ Prime[Range@PrimePi@n]
                    primesNest2[f, x, 10]



                    {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]]}




                    and



                    ClearAll[primesNest3]
                    primesNest3[f_, x_, n_] := Composition[## & @@ ConstantArray[f, #]][x] & /@
                    Prime[Range@PrimePi@n]
                    primesNest3[f, x, 10]


                    . {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]]}






                    share|improve this answer











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                      2












                      $begingroup$

                      Lets say you have f(x) and you want results up to 10



                      n=10;    
                      NestList[f,x,n][[#+1]]&/@Prime[Range@PrimePi@n]



                      {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]]}







                      share|improve this answer











                      $endgroup$


















                        2












                        $begingroup$

                        Lets say you have f(x) and you want results up to 10



                        n=10;    
                        NestList[f,x,n][[#+1]]&/@Prime[Range@PrimePi@n]



                        {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]]}







                        share|improve this answer











                        $endgroup$
















                          2












                          2








                          2





                          $begingroup$

                          Lets say you have f(x) and you want results up to 10



                          n=10;    
                          NestList[f,x,n][[#+1]]&/@Prime[Range@PrimePi@n]



                          {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]]}







                          share|improve this answer











                          $endgroup$



                          Lets say you have f(x) and you want results up to 10



                          n=10;    
                          NestList[f,x,n][[#+1]]&/@Prime[Range@PrimePi@n]



                          {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]]}








                          share|improve this answer














                          share|improve this answer



                          share|improve this answer








                          edited 6 hours ago

























                          answered 6 hours ago









                          J42161217J42161217

                          3,777321




                          3,777321























                              2












                              $begingroup$

                              Here's a way using Compose:



                              n = 10; ComposeList[ConstantArray[f, n], f[x]][[#]] & /@ Prime[Range@PrimePi@n]

                              {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]]}





                              share|improve this answer









                              $endgroup$


















                                2












                                $begingroup$

                                Here's a way using Compose:



                                n = 10; ComposeList[ConstantArray[f, n], f[x]][[#]] & /@ Prime[Range@PrimePi@n]

                                {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]]}





                                share|improve this answer









                                $endgroup$
















                                  2












                                  2








                                  2





                                  $begingroup$

                                  Here's a way using Compose:



                                  n = 10; ComposeList[ConstantArray[f, n], f[x]][[#]] & /@ Prime[Range@PrimePi@n]

                                  {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]]}





                                  share|improve this answer









                                  $endgroup$



                                  Here's a way using Compose:



                                  n = 10; ComposeList[ConstantArray[f, n], f[x]][[#]] & /@ Prime[Range@PrimePi@n]

                                  {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]]}






                                  share|improve this answer












                                  share|improve this answer



                                  share|improve this answer










                                  answered 5 hours ago









                                  bill sbill s

                                  53.4k376152




                                  53.4k376152























                                      2












                                      $begingroup$

                                      Here's a way to accumulate the nestings, i.e. use the previous nesting as the starting point for the next one:



                                      primeNest[f_, x_, n_] := FoldList[Nest[f, ##] &, f[f[x]], Differences[Prime[Range[n]]]]

                                      primeNest[f, x, 5]



                                      {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], 
                                      f[f[f[f[f[f[f[x]]]]]]], f[f[f[f[f[f[f[f[f[f[f[x]]]]]]]]]]]}



                                      (Depth /@ primeNest[f, x, 20]) - 1



                                      {2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71}






                                      share|improve this answer









                                      $endgroup$


















                                        2












                                        $begingroup$

                                        Here's a way to accumulate the nestings, i.e. use the previous nesting as the starting point for the next one:



                                        primeNest[f_, x_, n_] := FoldList[Nest[f, ##] &, f[f[x]], Differences[Prime[Range[n]]]]

                                        primeNest[f, x, 5]



                                        {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], 
                                        f[f[f[f[f[f[f[x]]]]]]], f[f[f[f[f[f[f[f[f[f[f[x]]]]]]]]]]]}



                                        (Depth /@ primeNest[f, x, 20]) - 1



                                        {2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71}






                                        share|improve this answer









                                        $endgroup$
















                                          2












                                          2








                                          2





                                          $begingroup$

                                          Here's a way to accumulate the nestings, i.e. use the previous nesting as the starting point for the next one:



                                          primeNest[f_, x_, n_] := FoldList[Nest[f, ##] &, f[f[x]], Differences[Prime[Range[n]]]]

                                          primeNest[f, x, 5]



                                          {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], 
                                          f[f[f[f[f[f[f[x]]]]]]], f[f[f[f[f[f[f[f[f[f[f[x]]]]]]]]]]]}



                                          (Depth /@ primeNest[f, x, 20]) - 1



                                          {2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71}






                                          share|improve this answer









                                          $endgroup$



                                          Here's a way to accumulate the nestings, i.e. use the previous nesting as the starting point for the next one:



                                          primeNest[f_, x_, n_] := FoldList[Nest[f, ##] &, f[f[x]], Differences[Prime[Range[n]]]]

                                          primeNest[f, x, 5]



                                          {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], 
                                          f[f[f[f[f[f[f[x]]]]]]], f[f[f[f[f[f[f[f[f[f[f[x]]]]]]]]]]]}



                                          (Depth /@ primeNest[f, x, 20]) - 1



                                          {2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71}







                                          share|improve this answer












                                          share|improve this answer



                                          share|improve this answer










                                          answered 4 hours ago









                                          Chip HurstChip Hurst

                                          21.3k15790




                                          21.3k15790























                                              1












                                              $begingroup$

                                              One can in fact use NestWhile along with NestList, in the same spirit as this previous answer:



                                              NestList[NestWhile[f, f[#], ! PrimeQ[Depth[#] - 1] &] &, x, 5]
                                              {x, f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]],
                                              f[f[f[f[f[f[f[f[f[f[f[x]]]]]]]]]]]}


                                              Here is another variation which yields the same result:



                                              NestList[Nest[f, #, NextPrime[Depth[#] - 1] - Depth[#] + 1] &, x, 5]





                                              share|improve this answer









                                              $endgroup$


















                                                1












                                                $begingroup$

                                                One can in fact use NestWhile along with NestList, in the same spirit as this previous answer:



                                                NestList[NestWhile[f, f[#], ! PrimeQ[Depth[#] - 1] &] &, x, 5]
                                                {x, f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]],
                                                f[f[f[f[f[f[f[f[f[f[f[x]]]]]]]]]]]}


                                                Here is another variation which yields the same result:



                                                NestList[Nest[f, #, NextPrime[Depth[#] - 1] - Depth[#] + 1] &, x, 5]





                                                share|improve this answer









                                                $endgroup$
















                                                  1












                                                  1








                                                  1





                                                  $begingroup$

                                                  One can in fact use NestWhile along with NestList, in the same spirit as this previous answer:



                                                  NestList[NestWhile[f, f[#], ! PrimeQ[Depth[#] - 1] &] &, x, 5]
                                                  {x, f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]],
                                                  f[f[f[f[f[f[f[f[f[f[f[x]]]]]]]]]]]}


                                                  Here is another variation which yields the same result:



                                                  NestList[Nest[f, #, NextPrime[Depth[#] - 1] - Depth[#] + 1] &, x, 5]





                                                  share|improve this answer









                                                  $endgroup$



                                                  One can in fact use NestWhile along with NestList, in the same spirit as this previous answer:



                                                  NestList[NestWhile[f, f[#], ! PrimeQ[Depth[#] - 1] &] &, x, 5]
                                                  {x, f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]],
                                                  f[f[f[f[f[f[f[f[f[f[f[x]]]]]]]]]]]}


                                                  Here is another variation which yields the same result:



                                                  NestList[Nest[f, #, NextPrime[Depth[#] - 1] - Depth[#] + 1] &, x, 5]






                                                  share|improve this answer












                                                  share|improve this answer



                                                  share|improve this answer










                                                  answered 3 hours ago









                                                  J. M. is computer-lessJ. M. is computer-less

                                                  96.7k10303461




                                                  96.7k10303461























                                                      0












                                                      $begingroup$

                                                      This may not be an elegant and smart way to do it but here is one way.



                                                        exp = NestList[g, x, 12];
                                                      selector = PrimeQ[LeafCount /@ exp - 1];
                                                      Pick[exp, selector] /. {g -> f, x -> x0}



                                                      {f[f[x0]], f[f[f[x0]]], f[f[f[f[f[x0]]]]], f[f[f[f[f[f[f[x0]]]]]]],
                                                      f[f[f[f[f[f[f[f[f[f[f[x0]]]]]]]]]]]}







                                                      share|improve this answer











                                                      $endgroup$


















                                                        0












                                                        $begingroup$

                                                        This may not be an elegant and smart way to do it but here is one way.



                                                          exp = NestList[g, x, 12];
                                                        selector = PrimeQ[LeafCount /@ exp - 1];
                                                        Pick[exp, selector] /. {g -> f, x -> x0}



                                                        {f[f[x0]], f[f[f[x0]]], f[f[f[f[f[x0]]]]], f[f[f[f[f[f[f[x0]]]]]]],
                                                        f[f[f[f[f[f[f[f[f[f[f[x0]]]]]]]]]]]}







                                                        share|improve this answer











                                                        $endgroup$
















                                                          0












                                                          0








                                                          0





                                                          $begingroup$

                                                          This may not be an elegant and smart way to do it but here is one way.



                                                            exp = NestList[g, x, 12];
                                                          selector = PrimeQ[LeafCount /@ exp - 1];
                                                          Pick[exp, selector] /. {g -> f, x -> x0}



                                                          {f[f[x0]], f[f[f[x0]]], f[f[f[f[f[x0]]]]], f[f[f[f[f[f[f[x0]]]]]]],
                                                          f[f[f[f[f[f[f[f[f[f[f[x0]]]]]]]]]]]}







                                                          share|improve this answer











                                                          $endgroup$



                                                          This may not be an elegant and smart way to do it but here is one way.



                                                            exp = NestList[g, x, 12];
                                                          selector = PrimeQ[LeafCount /@ exp - 1];
                                                          Pick[exp, selector] /. {g -> f, x -> x0}



                                                          {f[f[x0]], f[f[f[x0]]], f[f[f[f[f[x0]]]]], f[f[f[f[f[f[f[x0]]]]]]],
                                                          f[f[f[f[f[f[f[f[f[f[f[x0]]]]]]]]]]]}








                                                          share|improve this answer














                                                          share|improve this answer



                                                          share|improve this answer








                                                          edited 6 hours ago

























                                                          answered 6 hours ago









                                                          Okkes DulgerciOkkes Dulgerci

                                                          5,0021817




                                                          5,0021817























                                                              0












                                                              $begingroup$

                                                              Well, maybe not as elegant as with NestList, but for the first five primes (n=5), for example, here is another way



                                                              n = 5;
                                                              ls = {};
                                                              For [k = 0, k < n, k++,
                                                              (
                                                              Q = f[x];
                                                              For [j = 1, j < Prime[k + 1], j++,
                                                              Q = Map[f, Q];
                                                              ];
                                                              ls = Join[ls, {Q}]
                                                              )
                                                              ]
                                                              Print[ls]


                                                              Here is the result:



                                                              {f[f[x]],f[f[f[x]]],f[f[f[f[f[x]]]]],f[f[f[f[f[f[f[x]]]]]]],f[f[f[f[f[f[f[f[f[f[f[x]]]]]]]]]]]}





                                                              share|improve this answer










                                                              New contributor




                                                              mjw is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
                                                              Check out our Code of Conduct.






                                                              $endgroup$









                                                              • 1




                                                                $begingroup$
                                                                Why should I avoid the For loop in Mathematica?
                                                                $endgroup$
                                                                – corey979
                                                                6 hours ago










                                                              • $begingroup$
                                                                Yes, I've seen that! And I've got two loops! If n>10^4, great point! But for n=5 or n=10, do we care?, this code ran pretty quickly.
                                                                $endgroup$
                                                                – mjw
                                                                5 hours ago












                                                              • $begingroup$
                                                                Thank you for the tip, here it is with For replaced by Do: n = 5; ls = {}; Do [ ( Q = f[x]; Do [Q = Map[f, Q], {j, Range[Prime[k] - 1]}]; ls = Join[ls, {Q}] ), {k, Range[n]}] Print[ls]
                                                                $endgroup$
                                                                – mjw
                                                                5 hours ago


















                                                              0












                                                              $begingroup$

                                                              Well, maybe not as elegant as with NestList, but for the first five primes (n=5), for example, here is another way



                                                              n = 5;
                                                              ls = {};
                                                              For [k = 0, k < n, k++,
                                                              (
                                                              Q = f[x];
                                                              For [j = 1, j < Prime[k + 1], j++,
                                                              Q = Map[f, Q];
                                                              ];
                                                              ls = Join[ls, {Q}]
                                                              )
                                                              ]
                                                              Print[ls]


                                                              Here is the result:



                                                              {f[f[x]],f[f[f[x]]],f[f[f[f[f[x]]]]],f[f[f[f[f[f[f[x]]]]]]],f[f[f[f[f[f[f[f[f[f[f[x]]]]]]]]]]]}





                                                              share|improve this answer










                                                              New contributor




                                                              mjw is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
                                                              Check out our Code of Conduct.






                                                              $endgroup$









                                                              • 1




                                                                $begingroup$
                                                                Why should I avoid the For loop in Mathematica?
                                                                $endgroup$
                                                                – corey979
                                                                6 hours ago










                                                              • $begingroup$
                                                                Yes, I've seen that! And I've got two loops! If n>10^4, great point! But for n=5 or n=10, do we care?, this code ran pretty quickly.
                                                                $endgroup$
                                                                – mjw
                                                                5 hours ago












                                                              • $begingroup$
                                                                Thank you for the tip, here it is with For replaced by Do: n = 5; ls = {}; Do [ ( Q = f[x]; Do [Q = Map[f, Q], {j, Range[Prime[k] - 1]}]; ls = Join[ls, {Q}] ), {k, Range[n]}] Print[ls]
                                                                $endgroup$
                                                                – mjw
                                                                5 hours ago
















                                                              0












                                                              0








                                                              0





                                                              $begingroup$

                                                              Well, maybe not as elegant as with NestList, but for the first five primes (n=5), for example, here is another way



                                                              n = 5;
                                                              ls = {};
                                                              For [k = 0, k < n, k++,
                                                              (
                                                              Q = f[x];
                                                              For [j = 1, j < Prime[k + 1], j++,
                                                              Q = Map[f, Q];
                                                              ];
                                                              ls = Join[ls, {Q}]
                                                              )
                                                              ]
                                                              Print[ls]


                                                              Here is the result:



                                                              {f[f[x]],f[f[f[x]]],f[f[f[f[f[x]]]]],f[f[f[f[f[f[f[x]]]]]]],f[f[f[f[f[f[f[f[f[f[f[x]]]]]]]]]]]}





                                                              share|improve this answer










                                                              New contributor




                                                              mjw is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
                                                              Check out our Code of Conduct.






                                                              $endgroup$



                                                              Well, maybe not as elegant as with NestList, but for the first five primes (n=5), for example, here is another way



                                                              n = 5;
                                                              ls = {};
                                                              For [k = 0, k < n, k++,
                                                              (
                                                              Q = f[x];
                                                              For [j = 1, j < Prime[k + 1], j++,
                                                              Q = Map[f, Q];
                                                              ];
                                                              ls = Join[ls, {Q}]
                                                              )
                                                              ]
                                                              Print[ls]


                                                              Here is the result:



                                                              {f[f[x]],f[f[f[x]]],f[f[f[f[f[x]]]]],f[f[f[f[f[f[f[x]]]]]]],f[f[f[f[f[f[f[f[f[f[f[x]]]]]]]]]]]}






                                                              share|improve this answer










                                                              New contributor




                                                              mjw is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
                                                              Check out our Code of Conduct.









                                                              share|improve this answer



                                                              share|improve this answer








                                                              edited 5 hours ago





















                                                              New contributor




                                                              mjw is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
                                                              Check out our Code of Conduct.









                                                              answered 6 hours ago









                                                              mjwmjw

                                                              1065




                                                              1065




                                                              New contributor




                                                              mjw is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
                                                              Check out our Code of Conduct.





                                                              New contributor





                                                              mjw is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
                                                              Check out our Code of Conduct.






                                                              mjw is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
                                                              Check out our Code of Conduct.








                                                              • 1




                                                                $begingroup$
                                                                Why should I avoid the For loop in Mathematica?
                                                                $endgroup$
                                                                – corey979
                                                                6 hours ago










                                                              • $begingroup$
                                                                Yes, I've seen that! And I've got two loops! If n>10^4, great point! But for n=5 or n=10, do we care?, this code ran pretty quickly.
                                                                $endgroup$
                                                                – mjw
                                                                5 hours ago












                                                              • $begingroup$
                                                                Thank you for the tip, here it is with For replaced by Do: n = 5; ls = {}; Do [ ( Q = f[x]; Do [Q = Map[f, Q], {j, Range[Prime[k] - 1]}]; ls = Join[ls, {Q}] ), {k, Range[n]}] Print[ls]
                                                                $endgroup$
                                                                – mjw
                                                                5 hours ago
















                                                              • 1




                                                                $begingroup$
                                                                Why should I avoid the For loop in Mathematica?
                                                                $endgroup$
                                                                – corey979
                                                                6 hours ago










                                                              • $begingroup$
                                                                Yes, I've seen that! And I've got two loops! If n>10^4, great point! But for n=5 or n=10, do we care?, this code ran pretty quickly.
                                                                $endgroup$
                                                                – mjw
                                                                5 hours ago












                                                              • $begingroup$
                                                                Thank you for the tip, here it is with For replaced by Do: n = 5; ls = {}; Do [ ( Q = f[x]; Do [Q = Map[f, Q], {j, Range[Prime[k] - 1]}]; ls = Join[ls, {Q}] ), {k, Range[n]}] Print[ls]
                                                                $endgroup$
                                                                – mjw
                                                                5 hours ago










                                                              1




                                                              1




                                                              $begingroup$
                                                              Why should I avoid the For loop in Mathematica?
                                                              $endgroup$
                                                              – corey979
                                                              6 hours ago




                                                              $begingroup$
                                                              Why should I avoid the For loop in Mathematica?
                                                              $endgroup$
                                                              – corey979
                                                              6 hours ago












                                                              $begingroup$
                                                              Yes, I've seen that! And I've got two loops! If n>10^4, great point! But for n=5 or n=10, do we care?, this code ran pretty quickly.
                                                              $endgroup$
                                                              – mjw
                                                              5 hours ago






                                                              $begingroup$
                                                              Yes, I've seen that! And I've got two loops! If n>10^4, great point! But for n=5 or n=10, do we care?, this code ran pretty quickly.
                                                              $endgroup$
                                                              – mjw
                                                              5 hours ago














                                                              $begingroup$
                                                              Thank you for the tip, here it is with For replaced by Do: n = 5; ls = {}; Do [ ( Q = f[x]; Do [Q = Map[f, Q], {j, Range[Prime[k] - 1]}]; ls = Join[ls, {Q}] ), {k, Range[n]}] Print[ls]
                                                              $endgroup$
                                                              – mjw
                                                              5 hours ago






                                                              $begingroup$
                                                              Thank you for the tip, here it is with For replaced by Do: n = 5; ls = {}; Do [ ( Q = f[x]; Do [Q = Map[f, Q], {j, Range[Prime[k] - 1]}]; ls = Join[ls, {Q}] ), {k, Range[n]}] Print[ls]
                                                              $endgroup$
                                                              – mjw
                                                              5 hours ago













                                                              0












                                                              $begingroup$

                                                              ClearAll[primesNest0]
                                                              primesNest0[f_, x_, n_] := Nest[f, x, #] & /@ Prime[Range@PrimePi@n]
                                                              primesNest0[f, x, 10]



                                                              {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]]}




                                                              Also



                                                              ClearAll[primesNest1]
                                                              primesNest1[f_, x_, n_] := Fold[#2@# &, x, ConstantArray[f, #]] & /@ Prime[Range@PrimePi@n]

                                                              primesNest1[f, x, 10]



                                                              {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]]}




                                                              and



                                                              ClearAll[primesNest2]
                                                              primesNest2[f_, x_, n_] := Compose[##&@@ConstantArray[f, #], x] & /@ Prime[Range@PrimePi@n]
                                                              primesNest2[f, x, 10]



                                                              {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]]}




                                                              and



                                                              ClearAll[primesNest3]
                                                              primesNest3[f_, x_, n_] := Composition[## & @@ ConstantArray[f, #]][x] & /@
                                                              Prime[Range@PrimePi@n]
                                                              primesNest3[f, x, 10]


                                                              . {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]]}






                                                              share|improve this answer











                                                              $endgroup$


















                                                                0












                                                                $begingroup$

                                                                ClearAll[primesNest0]
                                                                primesNest0[f_, x_, n_] := Nest[f, x, #] & /@ Prime[Range@PrimePi@n]
                                                                primesNest0[f, x, 10]



                                                                {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]]}




                                                                Also



                                                                ClearAll[primesNest1]
                                                                primesNest1[f_, x_, n_] := Fold[#2@# &, x, ConstantArray[f, #]] & /@ Prime[Range@PrimePi@n]

                                                                primesNest1[f, x, 10]



                                                                {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]]}




                                                                and



                                                                ClearAll[primesNest2]
                                                                primesNest2[f_, x_, n_] := Compose[##&@@ConstantArray[f, #], x] & /@ Prime[Range@PrimePi@n]
                                                                primesNest2[f, x, 10]



                                                                {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]]}




                                                                and



                                                                ClearAll[primesNest3]
                                                                primesNest3[f_, x_, n_] := Composition[## & @@ ConstantArray[f, #]][x] & /@
                                                                Prime[Range@PrimePi@n]
                                                                primesNest3[f, x, 10]


                                                                . {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]]}






                                                                share|improve this answer











                                                                $endgroup$
















                                                                  0












                                                                  0








                                                                  0





                                                                  $begingroup$

                                                                  ClearAll[primesNest0]
                                                                  primesNest0[f_, x_, n_] := Nest[f, x, #] & /@ Prime[Range@PrimePi@n]
                                                                  primesNest0[f, x, 10]



                                                                  {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]]}




                                                                  Also



                                                                  ClearAll[primesNest1]
                                                                  primesNest1[f_, x_, n_] := Fold[#2@# &, x, ConstantArray[f, #]] & /@ Prime[Range@PrimePi@n]

                                                                  primesNest1[f, x, 10]



                                                                  {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]]}




                                                                  and



                                                                  ClearAll[primesNest2]
                                                                  primesNest2[f_, x_, n_] := Compose[##&@@ConstantArray[f, #], x] & /@ Prime[Range@PrimePi@n]
                                                                  primesNest2[f, x, 10]



                                                                  {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]]}




                                                                  and



                                                                  ClearAll[primesNest3]
                                                                  primesNest3[f_, x_, n_] := Composition[## & @@ ConstantArray[f, #]][x] & /@
                                                                  Prime[Range@PrimePi@n]
                                                                  primesNest3[f, x, 10]


                                                                  . {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]]}






                                                                  share|improve this answer











                                                                  $endgroup$



                                                                  ClearAll[primesNest0]
                                                                  primesNest0[f_, x_, n_] := Nest[f, x, #] & /@ Prime[Range@PrimePi@n]
                                                                  primesNest0[f, x, 10]



                                                                  {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]]}




                                                                  Also



                                                                  ClearAll[primesNest1]
                                                                  primesNest1[f_, x_, n_] := Fold[#2@# &, x, ConstantArray[f, #]] & /@ Prime[Range@PrimePi@n]

                                                                  primesNest1[f, x, 10]



                                                                  {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]]}




                                                                  and



                                                                  ClearAll[primesNest2]
                                                                  primesNest2[f_, x_, n_] := Compose[##&@@ConstantArray[f, #], x] & /@ Prime[Range@PrimePi@n]
                                                                  primesNest2[f, x, 10]



                                                                  {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]]}




                                                                  and



                                                                  ClearAll[primesNest3]
                                                                  primesNest3[f_, x_, n_] := Composition[## & @@ ConstantArray[f, #]][x] & /@
                                                                  Prime[Range@PrimePi@n]
                                                                  primesNest3[f, x, 10]


                                                                  . {f[f[x]], f[f[f[x]]], f[f[f[f[f[x]]]]], f[f[f[f[f[f[f[x]]]]]]]}







                                                                  share|improve this answer














                                                                  share|improve this answer



                                                                  share|improve this answer








                                                                  edited 4 hours ago

























                                                                  answered 5 hours ago









                                                                  kglrkglr

                                                                  184k10202420




                                                                  184k10202420






























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