OFFSET
0,4
LINKS
N. J. A. Sloane, Transforms
FORMULA
a(n) = [x^n] Product_{k>=1} 1/(1 + x^k)^binomial(n+k-2,n-1).
MATHEMATICA
Table[SeriesCoefficient[Exp[Sum[(-1)^k x^k/(k (1 - x^k)^n), {k, 1, n}]], {x, 0, n}], {n, 0, 24}]
Table[SeriesCoefficient[Product[1/(1 + x^k)^Binomial[n + k - 2, n - 1], {k, 1, n}], {x, 0, n}], {n, 0, 24}]
CROSSREFS
KEYWORD
sign
AUTHOR
Ilya Gutkovskiy, May 28 2018
STATUS
approved