A265833 Expansion of Product_{k>=1} 1/(1 - (5*k-3)*x^(5*k-3)).

1, 0, 2, 0, 4, 0, 8, 7, 16, 14, 32, 28, 76, 56, 201, 112, 402, 241, 804, 566, 1608, 1475, 3238, 2950, 6739, 5900, 14066, 11827, 30533, 24012, 61066, 49865, 122164, 103846, 245070, 224499, 494374, 449035, 1001635, 898992, 2032082, 1805626, 4181855, 3640890

Offset: 0

Author

Vaclav Kotesovec, Dec 16 2015

Keywords

• nonn

Links

• Vaclav Kotesovec, Table of n, a(n) for n = 0..5000

Crossrefs

Cf. A067553, A265820, A265821, A265828, A265829, A265830.

Cf. A265831, A265832, A265834.

Programs

Mathematica

nmax = 40; CoefficientList[Series[Product[1/(1 - (5*k-3)*x^(5*k-3)), {k, 1, nmax}], {x, 0, nmax}], x]

Formula

a(n) ~ c * 2^(n/2), where

c = 2.083307142076305100818196347525098347528893162823662452462... if n is even,

c = 1.350596787589129261746699661559125050005090208149022621867... if n is odd.