OFFSET
0,3
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..10000
FORMULA
a(n) = Sum_{k=0..n} (-1)^k * A066448(n,k).
G.f.: Sum_{k>=0} (-1)^k * x^(k^2) * Product_{j=1..k} (1+x^j)/(1-x^j).
PROG
(PARI) my(N=66, x='x+O('x^N)); Vec(sum(k=0, sqrtint(N), (-1)^k*x^k^2*prod(j=1, k, (1+x^j)/(1-x^j))))
CROSSREFS
KEYWORD
sign
AUTHOR
Seiichi Manyama, Jan 12 2022
STATUS
approved