A022647 Expansion of Product_{m>=1} (1 + m*q^m)^19.

1, 19, 209, 1748, 12217, 74898, 414865, 2116885, 10087480, 45348041, 193814402, 792340831, 3113639744, 11808753973, 43368768307, 154674601937, 537009888061, 1818759910067, 6019901796578, 19503777943838, 61940839239196, 193067981970548, 591298084019937

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn

Links

• G. C. Greubel, Table of n, a(n) for n = 0..1000

Crossrefs

Column k=19 of A297321.

Programs

Magma

Coefficients(&*[(1+m*x^m)^19:m in [1..40]])[1..40] where x is PolynomialRing(Integers()).1; // G. C. Greubel, Feb 17 2018

Maple

[seq(coeff(series(mul((1+m*q^m)^(19), m=1..100),q,101),q,j),j=0..25)]; # Muniru A Asiru, Feb 18 2018

Mathematica

With[{nmax = 50}, CoefficientList[Series[Product[(1 + k*q^k)^19, {k, 1, nmax}], {q, 0, nmax}], q]] (* G. C. Greubel, Feb 17 2018 *)

PARI

m=50; q='q+O('q^m); Vec(prod(n=1,m,(1+n*q^n)^19)) \\ G. C. Greubel, Feb 17 2018