OFFSET
0,2
FORMULA
E.g.f.: A(x) = ( (1/x) * Series_Reversion(x / (2 - exp(x))) )^2.
a(n) = 2 * (n+1)! * Sum_{k=0..n} (-1)^k * Stirling2(n,k)/(n-k+2)!.
PROG
(PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace((serreverse(x/(2-exp(x)))/x)^2))
(PARI) a(n) = 2*(n+1)!*sum(k=0, n, (-1)^k*stirling(n, k, 2)/(n-k+2)!);
CROSSREFS
KEYWORD
sign
AUTHOR
Seiichi Manyama, Sep 02 2024
STATUS
approved