A300583 Expansion of Product_{k>=1} 1 / (1 - 2*3^k*x^k).

1, 6, 54, 378, 2754, 17982, 121014, 765450, 4894506, 30429918, 189311094, 1160312850, 7113869226, 43228473822, 262556300286, 1587419581410, 9590551158474, 57795130268694, 348125978482686, 2093918636332530, 12590534397102930, 75647788993941174

Offset: 0

Author

Vaclav Kotesovec, Mar 09 2018

Keywords

• nonn
• changed

Crossrefs

Cf. A065446, A242587, A300582.

Programs

Mathematica

nmax = 25; CoefficientList[Series[Product[1/(1-2*3^k*x^k), {k, 1, nmax}], {x, 0, nmax}], x]

Formula

a(n) ~ c * 6^n, where c = A065446 = 1/QPochhammer(1/2) = 3.46274661945506361153...