%I #8 Dec 20 2023 12:36:53
%S 1,0,7,47,549,7859,134743,2694537,61595593,1584039383,45262146411,
%T 1422647401493,48780718512397,1812012517295811,72486789793754911,
%U 3106846273709042609,142039582571511632529,6899664100487740573871,354870658975988082859219
%N Expansion of e.g.f. exp(-x) / (1 - x*exp(3*x)).
%F a(n) = n! * Sum_{k=0..n} (3*(n-k)-1)^k / k!.
%o (PARI) a(n) = n!*sum(k=0, n, (3*(n-k)-1)^k/k!);
%Y Cf. A092148, A368294.
%K nonn,easy
%O 0,3
%A _Seiichi Manyama_, Dec 20 2023
|