A306664 Expansion of Sum_{k>=0} x^(k*(k+1)) / Product_{j=1..k} (1 - x^j)^j.

1, 0, 1, 1, 1, 1, 2, 2, 4, 4, 7, 7, 12, 12, 19, 22, 31, 37, 54, 63, 89, 111, 146, 184, 247, 301, 398, 501, 642, 804, 1042, 1293, 1663, 2082, 2648, 3321, 4229, 5268, 6691, 8370, 10553, 13168, 16595, 20659, 25929, 32253, 40321, 50092, 62489, 77418, 96340, 119266, 147998, 182927, 226609

Offset

0,7

Links

Table of n, a(n) for n=0..54.

Mathematica

nmax = 54; CoefficientList[Series[Sum[x^(k (k + 1))/Product[(1 - x^j)^j, {j, 1, k}], {k, 0, nmax}], {x, 0, nmax}], x]

Crossrefs

Cf. A003106, A206100, A206138.

Sequence in context: A363214 A062896 A025065 * A365826 A131524 A089075

Adjacent sequences: A306661 A306662 A306663 * A306665 A306666 A306667

Keyword

nonn

Author

Ilya Gutkovskiy, Mar 04 2019

Status

approved