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A307128 Expansion of Product_{j>=1} (1 + (-1 + Product_{k>=1} (1 + x^k))^j). 6
1, 1, 2, 6, 15, 40, 103, 266, 683, 1753, 4481, 11417, 28993, 73414, 185424, 467302, 1175322, 2950467, 7393090, 18492029, 46173538, 115102596, 286482967, 711990108, 1767048214, 4379814978, 10842382074, 26808912074, 66212421302, 163351562975, 402575169429, 991119918949 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..31.

FORMULA

G.f.: q(q(x) - 1), where q(x) = g.f. of A000009 (number of partitions into distinct parts).

MATHEMATICA

nmax = 31; CoefficientList[Series[Product[(1 + (-1 + Product[(1 + x^k), {k, 1, nmax}])^j), {j, 1, nmax}], {x, 0, nmax}], x]

CROSSREFS

Cf. A000009, A307127.

Sequence in context: A321646 A246563 A259399 * A172399 A001654 A062106

Adjacent sequences:  A307125 A307126 A307127 * A307129 A307130 A307131

KEYWORD

nonn

AUTHOR

Ilya Gutkovskiy, Mar 26 2019

STATUS

approved

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Last modified February 24 06:13 EST 2020. Contains 332199 sequences. (Running on oeis4.)