This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A379991 #7 Jan 08 2025 05:46:33
%S A379991 1,5,34,293,3052,37247,520918,8211065,143997160,2780465147,
%T A379991 58611713434,1339236707525,32969142927580,869913580853735,
%U A379991 24490615055384062,732751463209179953,23217990692393685712,776689510407852177011,27353286267329098887202
%N A379991 Expansion of e.g.f. exp(-x)/(exp(-x) - x)^3.
%F A379991 a(n) = n! * Sum_{k=0..n} (k+2)^(n-k) * binomial(k+2,2)/(n-k)!.
%o A379991 (PARI) a(n) = n!*sum(k=0, n, (k+2)^(n-k)*binomial(k+2, 2)/(n-k)!);
%Y A379991 Cf. A377530, A379942, A379990.
%K A379991 nonn,easy
%O A379991 0,2
%A A379991 _Seiichi Manyama_, Jan 07 2025