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.

A303552 Number of periodic multisets of compositions of total weight n.

Original entry on oeis.org

0, 1, 1, 3, 1, 9, 1, 18, 7, 44, 1, 119, 1, 246, 48, 585, 1, 1470, 1, 3248, 250, 7535, 1, 18114, 42, 40593, 1373, 93726, 1, 218665, 1, 493735, 7539, 1127981, 285, 2587962, 1, 5841445, 40597, 13244166, 1, 30047413, 1, 67604050, 216745, 152258273, 1, 342747130
Offset: 1

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Author

Gus Wiseman, Apr 26 2018

Keywords

Comments

A multiset is periodic if its multiplicities have a common divisor greater than 1.

Examples

			The a(6) = 9 periodic multisets of compositions are:
{1,1,1,1,1,1},
{1,1,2,2}, {1,1,11,11},
{2,2,2}, {11,11,11},
{3,3}, {21,21}, {12,12}, {111,111}.
		

Crossrefs

Programs

  • Mathematica
    nn=60;
    ser=Product[1/(1-x^n)^2^(n-1),{n,nn}]
    Table[SeriesCoefficient[ser,{x,0,n}]-Sum[MoebiusMu[d]*SeriesCoefficient[ser,{x,0,n/d}],{d,Divisors[n]}],{n,1,nn}]