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A305205
a(n) = [x^n] exp(-Sum_{k>=1} x^k/(k*(1 - x^k)^n)).
2
1, -1, -2, -3, -4, 30, 274, 1841, 9358, 32463, -41557, -2265846, -28939286, -272101778, -2038274408, -10494221259, 9056975574, 1244820826687, 22703501504125, 299864024917632, 3221417281127823, 26849622543478562, 110101743392268978, -1810492304600468063
OFFSET
0,3
LINKS
FORMULA
a(n) = [x^n] Product_{k>=1} (1 - x^k)^binomial(n+k-2,n-1).
MATHEMATICA
Table[SeriesCoefficient[Exp[-Sum[x^k/(k (1 - x^k)^n), {k, 1, n}]], {x, 0, n}], {n, 0, 23}]
Table[SeriesCoefficient[Product[(1 - x^k)^Binomial[n + k - 2, n - 1], {k, 1, n}], {x, 0, n}], {n, 0, 23}]
CROSSREFS
KEYWORD
sign
AUTHOR
Ilya Gutkovskiy, May 27 2018
STATUS
approved