OFFSET
0,4
FORMULA
a(n) = (1/(n+1)) * Sum_{k=0..n} (-1)^k * binomial(n+1,k) * binomial(2*k,n-k).
PROG
(PARI) a(n) = sum(k=0, n, (-1)^k*binomial(n+1, k)*binomial(2*k, n-k))/(n+1);
CROSSREFS
KEYWORD
sign
AUTHOR
Seiichi Manyama, Aug 05 2023
STATUS
approved