OFFSET
0,3
FORMULA
a(n) = Sum_{k=0..n} 3^(n-k) * Stirling2(n,k) * Bell(k).
PROG
(PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(exp(exp((exp(3*x)-1)/3)-1)))
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Jan 17 2025
STATUS
approved
