cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A329607 a(n) = A007947(A122111(n)).

Original entry on oeis.org

1, 2, 2, 3, 2, 6, 2, 5, 3, 6, 2, 10, 2, 6, 6, 7, 2, 15, 2, 10, 6, 6, 2, 14, 3, 6, 5, 10, 2, 30, 2, 11, 6, 6, 6, 21, 2, 6, 6, 14, 2, 30, 2, 10, 10, 6, 2, 22, 3, 15, 6, 10, 2, 35, 6, 14, 6, 6, 2, 42, 2, 6, 10, 13, 6, 30, 2, 10, 6, 30, 2, 33, 2, 6, 15, 10, 6, 30, 2, 22, 7, 6, 2, 42, 6, 6, 6, 14, 2, 70, 6, 10, 6, 6, 6, 26, 2, 15, 10, 21, 2, 30, 2, 14, 30
Offset: 1

Views

Author

Antti Karttunen, Nov 17 2019

Keywords

Crossrefs

Programs

  • Mathematica
    Block[{f}, f[1] = 1; f[n_] := Module[{l = #, m = 0}, Times @@ Power @@@ Table[l -= m; l = DeleteCases[l, 0]; {Prime@ Length@ l, m = Min@ l}, Length@ Union@ l]] &@ Catenate[ConstantArray[PrimePi[#1], #2] & @@@ FactorInteger@ n]; Array[If[# < 1, 0, Sum[EulerPhi[d] Abs@ MoebiusMu[d], {d, Divisors[#]}]] &@ f[#] &, 105]] (* Michael De Vlieger, Nov 18 2019, after JungHwan Min at A122111. *)
  • PARI
    A007947(n) = factorback(factorint(n)[, 1]);
    A064989(n) = {my(f); f = factor(n); if((n>1 && f[1,1]==2), f[1,2] = 0); for (i=1, #f~, f[i,1] = precprime(f[i,1]-1)); factorback(f)};
    A122111(n) = if(1==n,n,prime(bigomega(n))*A122111(A064989(n)));
    A329607(n) = A007947(A122111(n));

Formula

a(n) = A122111(A071364(n)).
A181821(a(n)) = A329600(n).