OFFSET
0,5
LINKS
Eric Weisstein's World of Mathematics, Lambert W-Function.
FORMULA
a(n) = n! * Sum_{k=0..floor(n/3)} k^(n-2*k) / (6^k * k! * (n-3*k)!).
PROG
(PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(1/(1+lambertw(-x^3/6*exp(x)))))
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Seiichi Manyama, Apr 30 2023
STATUS
approved