OFFSET
-2,4
FORMULA
a(-2) = 1; a(n) = -Sum_{k=1..n+2} A010051(k+2) * a(n-k).
PROG
(PARI) my(N=40, x='x+O('x^N)); Vec(1/sum(k=1, N, isprime(k)*x^k))
(PARI) a(n) = if(n==-2, 1, -sum(k=1, n+2, isprime(k+2)*a(n-k)));
CROSSREFS
KEYWORD
sign
AUTHOR
Seiichi Manyama, Mar 17 2022
STATUS
approved