OFFSET
0,2
FORMULA
a(n) = Sum_{k=0..n} 3^k * Stirling2(n,k) * Bell(k) = Sum_{k=0..n} Stirling2(n,k) * A247452(k).
PROG
(PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace(exp(exp(3*(exp(x)-1))-1)))
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Feb 01 2024
STATUS
approved