OFFSET
0,2
FORMULA
G.f.: B(x)^4 where B(x) is the g.f. of A106228.
a(n) = 2 * Sum_{k=0..n} binomial(n,k) * binomial(n/2+3*k/2+2,n)/(n/2+3*k/2+2).
PROG
(PARI) a(n) = 2*sum(k=0, n, binomial(n, k)*binomial(n/2+3*k/2+2, n)/(n/2+3*k/2+2));
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Apr 04 2024
STATUS
approved