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 A292308 #12 Sep 14 2017 09:30:57
%S A292308 1,-1,1,-4,21,-96,520,-3795,32053,-284368,2763876,-30648465,373339824,
%T A292308 -4833294389,67167087793,-1009753574739,16215467043493,
%U A292308 -275361718915824,4947532173402532,-94054153646919213,1882793796608183356,-39528099512321898363
%N A292308 E.g.f.: 1/Product_{k>=1} (1 + x^k/k!).
%F A292308 a(n) = (-1)^n * A076901(n).
%F A292308 a(n) ~ c * (-1)^n * n!, where c = Product_{k>=2} (1 + (-1)^k/k!) = 0.77351587386... - _Vaclav Kotesovec_, Sep 14 2017
%t A292308 nmax = 20; Table[SeriesCoefficient[Product[1/(1 + x^k/k!), {k, 1, n}], {x, 0, n}], {n, 0, nmax}] * Range[0, nmax]! (* _Vaclav Kotesovec_, Sep 14 2017 *)
%Y A292308 Cf. A005651, A007837, A076901.
%K A292308 sign
%O A292308 0,4
%A A292308 _Seiichi Manyama_, Sep 14 2017