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 A279280 Expansion of Product_{k>=1} (1 + x^(k*(5*k-3)/2)). 5
 1, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 2, 1, 0, 0, 0, 0, 0, 1, 2, 1, 0, 0, 0, 0, 0, 1, 1, 0, 1, 1, 0, 0, 0, 0, 0, 1, 2, 1, 0, 0, 0, 1, 1, 1, 2, 1, 0, 0, 1, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,82 COMMENTS Number of partitions of n into distinct heptagonal numbers (A000566). LINKS Eric Weisstein's World of Mathematics, Heptagonal Number FORMULA G.f.: Product_{k>=1} (1 + x^(k*(5*k-3)/2)). EXAMPLE a(81) = 2 because we have [81] and [55, 18, 7, 1]. MATHEMATICA nmax = 120; CoefficientList[Series[Product[1 + x^(k (5 k - 3)/2), {k, 1, nmax}], {x, 0, nmax}], x] CROSSREFS Cf. A000566, A024940, A033461, A218380, A279012, A279279, A279281. Sequence in context: A263338 A103522 A101108 * A284093 A284095 A279593 Adjacent sequences:  A279277 A279278 A279279 * A279281 A279282 A279283 KEYWORD nonn AUTHOR Ilya Gutkovskiy, Dec 09 2016 STATUS approved

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Last modified December 5 23:38 EST 2021. Contains 349558 sequences. (Running on oeis4.)