A362274 - OEIS

%I #13 Apr 15 2023 06:27:58

%S 1,1,4,27,232,2465,31416,467173,7940080,151824177,3225664720,

%T 75386002901,1921987809336,53085088574713,1578989028324904,

%U 50320957240554645,1710595789688360416,61783832256587799137,2362794061464082513440,95380148553556615501717

%N Expansion of e.g.f. 1/(1-x*exp(x*exp(x))).

%H Winston de Greef, <a href="/A362274/b362274.txt">Table of n, a(n) for n = 0..398</a>

%F a(n) = n! * Sum_{i=0..n} Sum_{j=0..n-i} i^j * j^(n-i-j) / (j! * (n-i-j)!).

%o (PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace(1/(1-x*exp(x*exp(x)))))

%Y Cf. A000949, A362273, A362275.

%Y Cf. A362245.

%K nonn

%O 0,3

%A _Seiichi Manyama_, Apr 13 2023