A306732 Expansion of Sum_{k>=0} x^(k*(k+1)/2) * Product_{j=1..k} (1 + j*x^j).

1, 1, 1, 1, 1, 2, 3, 1, 2, 5, 4, 7, 8, 5, 7, 11, 15, 22, 17, 31, 39, 20, 31, 39, 64, 81, 85, 125, 97, 170, 211, 121, 167, 229, 265, 385, 531, 548, 573, 814, 686, 1150, 1339, 860, 1131, 1344, 1888, 2109, 2780, 3656, 4127, 4294, 4498, 6320, 5568, 8747, 10260, 6856, 8673, 10580

Offset

0,6

Links

Table of n, a(n) for n=0..59.

Mathematica

nmax = 59; CoefficientList[Series[Sum[x^(k (k + 1)/2) Product[(1 + j x^j), {j, 1, k}], {k, 0, nmax}], {x, 0, nmax}], x]

Crossrefs

Cf. A053261, A204856, A306704.

Sequence in context: A050981 A053452 A023986 * A109202 A362599 A245559

Adjacent sequences: A306729 A306730 A306731 * A306733 A306734 A306735

Keyword

nonn

Author

Ilya Gutkovskiy, Mar 06 2019

Status

approved