A261635 Expansion of Product_{k>=0} 1/(1-x^(3*k+1))^4.

1, 4, 10, 20, 39, 72, 124, 204, 331, 524, 806, 1216, 1813, 2660, 3846, 5500, 7790, 10916, 15158, 20880, 28544, 38736, 52226, 69972, 93200, 123460, 162700, 213340, 278459, 361860, 468252, 603484, 774844, 991220, 1263576, 1605392, 2033172, 2566972, 3231338

Offset

0,2

Links

Table of n, a(n) for n=0..38.

Formula

a(n) ~ exp(2*Pi*sqrt(2*n)/3) * Gamma(1/3)^4 / (8 * 2^(1/12) * sqrt(3) * Pi^(8/3) * n^(5/12)).

Mathematica

nmax=50; CoefficientList[Series[Product[1/(1-x^(3*k+1))^4, {k, 0, nmax}], {x, 0, nmax}], x]

Crossrefs

Cf. A035382, A261616, A261636.

Sequence in context: A279262 A168673 A090164 * A258346 A128640 A128641

Adjacent sequences: A261632 A261633 A261634 * A261636 A261637 A261638

Keyword

nonn

Author

Vaclav Kotesovec, Aug 27 2015

Status

approved