A285472 Expansion of Product_{k>=1} ((1 + x^(4*k)) / (1 - x^k)).

1, 1, 2, 3, 6, 8, 13, 18, 28, 38, 55, 74, 106, 140, 192, 253, 342, 444, 588, 758, 992, 1267, 1634, 2072, 2650, 3334, 4218, 5276, 6627, 8234, 10262, 12682, 15708, 19308, 23764, 29070, 35597, 43340, 52792, 64008, 77622, 93724, 113160, 136124, 163712, 196225

Offset

0,3

Links

Table of n, a(n) for n=0..45.

Formula

a(n) ~ sqrt(3) * exp(sqrt(3*n)*Pi/2) / (16*n).

Mathematica

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

Crossrefs

Cf. A006950, A015128, A279328, A266648, A285460.

Sequence in context: A295342 A226635 A024788 * A318027 A373295 A004101

Adjacent sequences: A285469 A285470 A285471 * A285473 A285474 A285475

Keyword

nonn

Author

Vaclav Kotesovec, Apr 19 2017

Status

approved