A266945 Expansion of Product_{k>=1} 1 / (1 - 2*x^k)^3.

1, 6, 30, 122, 450, 1518, 4830, 14586, 42330, 118622, 322974, 857298, 2226586, 5672046, 14205654, 35040722, 85269114, 204971478, 487307542, 1146995154, 2675265522, 6188176838, 14205568950, 32383725450, 73352114450, 165171276822, 369904716750, 824244212554

Offset

0,2

Links

Vaclav Kotesovec, Table of n, a(n) for n = 0..1000

Formula

a(n) ~ c * n^2 * 2^n, where c = 1/(2*A048651^3) = 1/(2*QPochhammer(1/2)^3) = 20.760229307499152409838537... .

Mathematica

nmax = 40; CoefficientList[Series[Product[1/(1-2*x^k)^3, {k, 1, nmax}], {x, 0, nmax}], x]

Crossrefs

Cf. A070933, A266943.

Sequence in context: A371036 A215225 A056385 * A369819 A073970 A074009

Adjacent sequences: A266942 A266943 A266944 * A266946 A266947 A266948

Keyword

nonn

Author

Vaclav Kotesovec, Jan 06 2016

Status

approved