OFFSET
0,3
FORMULA
E.g.f.: B(x)^2, where B(x) is the e.g.f. of A371273.
a(n) = (2 * n!/(3*n+2)!) * Sum_{k=0..floor(n/2)} (3*n+k+1)! * Stirling2(n-k,k)/(n-k)!.
PROG
(PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace((serreverse(x*(1-x*(exp(x)-1))^3)/x)^(2/3)))
(PARI) a(n) = 2*n!*sum(k=0, n\2, (3*n+k+1)!*stirling(n-k, k, 2)/(n-k)!)/(3*n+2)!;
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Sep 22 2024
STATUS
approved