OFFSET
0,4
FORMULA
G.f.: exp( Sum_{k>=1} A370106(k) * x^k/k ).
a(n) = (1/(n+1)) * Sum_{k=0..n} (-1)^k * binomial(2*(n+1),k) * binomial(3*(n+1),n-k).
a(n) = (1/(n+1)) * [x^n] ( (1-x)^2 * (1+x)^3 )^(n+1).
PROG
(PARI) a(n) = sum(k=0, n, (-1)^k * binomial(2*(n+1), k)*binomial(3*(n+1), n-k))/(n+1);
(PARI) my(x='x+O('x^30)); Vec(serreverse(x/((1-x)^2*(1+x)^3))/x) \\ Michel Marcus, Feb 10 2024
CROSSREFS
KEYWORD
sign
AUTHOR
Seiichi Manyama, Feb 10 2024
STATUS
approved