OFFSET
0,2
COMMENTS
This sequence is obtained from the generalized Euler transform in A266964 by taking f(n) = -1/2, g(n) = 4.
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..1000
FORMULA
a(n) ~ -c * 2^(2*n-1) / (sqrt(Pi) * n^(3/2)), where c = QPochhammer[1/4]^(1/2) = 0.8297816201389011939293261374110190... - Vaclav Kotesovec, Apr 25 2018
MAPLE
seq(coeff(series(mul((1-4*x^k)^(1/2), k = 1..n), x, n+1), x, n), n=0..40); # Muniru A Asiru, Apr 22 2018
PROG
(PARI) N=66; x='x+O('x^N); Vec(prod(k=1, N, (1-4*x^k)^(1/2)))
CROSSREFS
KEYWORD
sign
AUTHOR
Seiichi Manyama, Apr 22 2018
STATUS
approved