A300581 Expansion of Product_{k>=1} 1/(1 - 2^(k+1)*x^k).

1, 4, 24, 112, 544, 2368, 10624, 44800, 190976, 791552, 3282944, 13414400, 54829056, 222117888, 899383296, 3625123840, 14601027584, 58659700736, 235555782656, 944552017920, 3786334535680, 15166305468416, 60736264994816, 243129089261568, 973133053952000

Offset: 0

Author

Vaclav Kotesovec, Mar 09 2018

Keywords

• nonn

Crossrefs

Cf. A075900, A300579.

Cf. A023882, A077365, A179381, A300520.

Programs

Mathematica

nmax = 25; CoefficientList[Series[Product[1/(1-2^(k+1)*x^k), {k, 1, nmax}], {x, 0, nmax}], x]

Formula

a(n) ~ c * 4^n, where c = A065446 = 1/QPochhammer(1/2) = 3.46274661945506361...