OFFSET
0,3
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..449
D. H. Lehmer, On reciprocally weighted partitions, Acta Arithmetica XXI (1972), 379-388 (Theorem 5).
FORMULA
a(n) ~ 2*exp(-gamma/2) * sqrt(2*n) * n! / Pi, where gamma is the Euler-Mascheroni constant A001620 [Lehmer, 1972]. - Vaclav Kotesovec, Jul 23 2019
MATHEMATICA
nmax = 30; CoefficientList[Series[1/Product[(1-x^(2*k-1)/(2*k-1)), {k, 1, Floor[nmax/2] + 1}], {x, 0, nmax}], x] * Range[0, nmax]! (* Vaclav Kotesovec, Nov 02 2017 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Nov 01 2017
STATUS
approved