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.

A133732 A054525 * A000041.

Original entry on oeis.org

1, 0, 1, 2, 4, 5, 10, 12, 20, 25, 41, 47, 76, 90, 129, 161, 230, 270, 384, 458, 615, 750, 1001, 1187, 1570, 1881, 2414, 2907, 3717, 4400, 5603, 6666, 8306, 9912, 12295, 14537, 17976, 21252, 25937, 30683, 37337, 43861, 53173, 62467, 75020, 88132
Offset: 1

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Author

Gary W. Adamson, Sep 22 2007

Keywords

Comments

A000041 = (1, 1, 2, 3, 5, 7, 11, 15, 22, 30, 42, 56, 77, ...).

Examples

			a(4) = 2 = (0, -1, 0, 1) dot (1, 1, 2, 3) = (0, -1, 0, 3).
		

Crossrefs

Cf. A054525.

Programs

  • Maple
    read("transforms") : A000041 := proc(n) combinat[numbpart](n) ; end: a000041 := [seq(A000041(n),n=0..150)] ; a133732 := MOBIUS(a000041) ; # R. J. Mathar, Jan 19 2009
    mob := (m,n) -> if irem(m,n) = 0 then numtheory:-mobius(m/n) else 0 fi:
    A133732 := n -> add(mob(n,d)*combinat:-numbpart(d-1), d=1..n):
    seq(A133732(n), n=1..46); # Peter Luschny, Jan 20 2018
  • Mathematica
    a[n_] := DivisorSum[n, MoebiusMu[n/#]*PartitionsP[#-1]&];
    Table[a[n], {n, 1, 45}] (* Jean-François Alcover, Jan 20 2018 *)

Formula

Möbius transform of A000041, the partition numbers.

Extensions

More terms from R. J. Mathar, Jan 19 2009
Offset set to 1 by Peter Luschny, Jan 20 2018