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 A355338 #17 Jun 29 2022 10:15:06
%S A355338 1,1,0,-1,3,12,-7,-47,332,1347,-2105,-4200,135457,474697,-900832,
%T A355338 4682135,126196787,439488524,233313817,19129265609,239146712732,
%U A355338 1104038984091,5891696027079,89831511761320,911995655018817,6253185308181553,54873149768926624,653039078246798383
%N A355338 Expansion of e.g.f.: exp(exp(x) - x^2 - 1).
%H A355338 Vaclav Kotesovec, <a href="/A355338/b355338.txt">Table of n, a(n) for n = 0..578</a>
%F A355338 a(n) ~ n^n * exp(n/LambertW(n) - LambertW(n)^2 - n - 1) / (sqrt(1 + LambertW(n)) * LambertW(n)^n).
%F A355338 a(n) ~ Bell(n) / exp(LambertW(n)^2).
%F A355338 a(0) = a(1) = 1; a(n) = -2 * (n-1) * a(n-2) + Sum_{k=1..n} binomial(n-1,k-1) * a(n-k). - _Seiichi Manyama_, Jun 29 2022
%t A355338 nmax = 30; CoefficientList[Series[Exp[Exp[x] - x^2 - 1], {x, 0, nmax}], x] * Range[0, nmax]!
%o A355338 (PARI) my(x='x+O('x^30)); Vec(serlaplace(exp(exp(x) - x^2 - 1))) \\ _Michel Marcus_, Jun 29 2022
%Y A355338 Cf. A000296, A277381, A316778, A355337.
%K A355338 sign
%O A355338 0,5
%A A355338 _Vaclav Kotesovec_, Jun 29 2022