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Expansion of e.g.f. exp(-x) / (1 - x*exp(3*x)).
1

%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