OFFSET
-2,5
FORMULA
a(-2) = 1; a(n) = -Sum_{k=1..n+2} A010051(2*k+3) * a(n-k).
EXAMPLE
G.f.: 1/x^3 - 1/x + x^3 - 2*x^5 + x^7 + 2*x^9 - 5*x^11 + ... .
PROG
(PARI) my(N=66, x='x+O('x^N)); Vec(1/sum(k=1, N, isprime(2*k-1)*x^k))
(PARI) a(n) = if(n==-2, 1, -sum(k=1, n+2, isprime(2*k+3)*a(n-k)));
CROSSREFS
KEYWORD
sign
AUTHOR
Seiichi Manyama, Mar 17 2022
STATUS
approved