A307566 Expansion of Product_{j>=1} (1 + j*(-1 + Product_{k>=1} (1 + k*x^k))^j).

1, 1, 4, 18, 72, 289, 1119, 4301, 16408, 62313, 234914, 879822, 3274623, 12125348, 44707778, 164258803, 601535222, 2195926654, 7990792367, 28985219498, 104811279467, 377875493610, 1358584361039, 4872111113570, 17431266435024, 62229179950735, 221699783190996, 788274748711694

Offset

0,3

Links

Table of n, a(n) for n=0..27.

Formula

G.f.: g(g(x) - 1), where g(x) = g.f. of A022629.

Mathematica

nmax = 27; CoefficientList[Series[Product[(1 + j (-1 + Product[(1 + k x^k), {k, 1, nmax}])^j), {j, 1, nmax}], {x, 0, nmax}], x]

Crossrefs

Cf. A022629, A307128, A307323, A307494.

Sequence in context: A027261 A290919 A218892 * A117615 A267450 A199524

Adjacent sequences: A307563 A307564 A307565 * A307567 A307568 A307569

Keyword

nonn

Author

Ilya Gutkovskiy, Apr 15 2019

Status

approved