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 A368294 #7 Dec 20 2023 12:36:57
%S A368294 1,0,5,26,257,3004,42277,694182,13027233,275027480,6451456421,
%T A368294 166468606930,4685926374241,142896198878484,4692784128725253,
%U A368294 165121528707826334,6197343209916830657,247136182723119609520,10434957969449887989445,465078400154112693602826
%N A368294 Expansion of e.g.f. exp(-x) / (1 - x*exp(2*x)).
%F A368294 a(n) = n! * Sum_{k=0..n} (2*(n-k)-1)^k / k!.
%o A368294 (PARI) a(n) = n!*sum(k=0, n, (2*(n-k)-1)^k/k!);
%Y A368294 Cf. A092148, A368295.
%K A368294 nonn,easy
%O A368294 0,3
%A A368294 _Seiichi Manyama_, Dec 20 2023