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.

A365519 Moebius inversion of A015134.

Original entry on oeis.org

1, 1, 1, 2, 2, 1, 3, 4, 3, 2, 13, 4, 6, 3, 8, 8, 8, 9, 21, 8, 24, 13, 11, 16, 10, 6, 9, 12, 62, 8, 33, 16, 24, 24, 24, 36, 18, 63, 24, 32, 42, 24, 21, 48, 24, 33, 69, 64, 21, 10, 32, 24, 26, 27, 144, 48, 40, 62, 61, 32, 62, 99, 72, 32, 48, 24, 33, 96, 88, 24
Offset: 1

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Author

Jay Anderson, Sep 07 2023

Keywords

Examples

			For n=4, the a(4) = 2 cycles counted are
  {0 1 1 2 3 1} repeating
  {0 3 3 2 1 3} repeating
There are 2 other cycles {0} and {0 2 2} mod 4 which are not counted because they are multiples of cycles counted at earlier n (n=1 for {0} and n=2 for {0 1 1}*2 = {0 2 2}).
		

Crossrefs

Programs

  • Mathematica
    a[n_]:=Sum[MoebiusMu[d]Part[ResourceFunction["OEISSequence"]["A015134"],n/d],{d,Divisors[n]}]; Array[a,70] (* Stefano Spezia, Sep 27 2023 *)

Formula

a(n) = Sum_{d|n} moebius(d)*A015134(n/d).
A015134(n) = Sum_{d|n} a(d).