OFFSET
0,3
FORMULA
a(n) = (-1)^n * n! * Sum_{k=0..n} 9^k * binomial((n-k)/3,k)/(n-k)!.
PROG
(PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace(exp(-x*(1-9*x)^(1/3))))
CROSSREFS
KEYWORD
sign,easy
AUTHOR
Seiichi Manyama, Apr 10 2023
STATUS
approved