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%I #5 Dec 10 2016 08:55:29
%S 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,
%T 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,
%U 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
%N Expansion of Product_{k>=1} (1 + x^(k*(5*k-3)/2)).
%C Number of partitions of n into distinct heptagonal numbers (A000566).
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/HeptagonalNumber.html">Heptagonal Number</a>
%H <a href="/index/Pol#polygonal_numbers">Index to sequences related to polygonal numbers</a>
%H <a href="/index/Par#partN">Index entries for related partition-counting sequences</a>
%F G.f.: Product_{k>=1} (1 + x^(k*(5*k-3)/2)).
%e a(81) = 2 because we have [81] and [55, 18, 7, 1].
%t nmax = 120; CoefficientList[Series[Product[1 + x^(k (5 k - 3)/2), {k, 1, nmax}], {x, 0, nmax}], x]
%Y Cf. A000566, A024940, A033461, A218380, A279012, A279279, A279281.
%K nonn
%O 0,82
%A _Ilya Gutkovskiy_, Dec 09 2016