OFFSET
0,8
FORMULA
G.f.: Product_{k>=1} ((1 + x^(2*k-1))/(1 + x^(2*k)))^k.
MATHEMATICA
nmax = 60; CoefficientList[Series[Product[((1 + x^(2 k - 1))/(1 + x^(2 k)))^k, {k, 1, nmax}], {x, 0, nmax}], x]
CROSSREFS
KEYWORD
sign
AUTHOR
Ilya Gutkovskiy, Dec 03 2017
STATUS
approved