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 A336950 #15 Feb 20 2022 06:42:12
%S A336950 1,1,6,42,392,4600,64752,1063216,19952256,421227648,9880951040,
%T A336950 254960721664,7176891675648,218857588139008,7187394935347200,
%U A336950 252897556424140800,9491754142468702208,378509920569294684160,15982018774576565649408,712306819507400060502016
%N A336950 E.g.f.: 1 / (1 - x * exp(2*x)).
%H A336950 Seiichi Manyama, <a href="/A336950/b336950.txt">Table of n, a(n) for n = 0..394</a>
%F A336950 a(n) = n! * Sum_{k=0..n} (2 * (n-k))^k / k!.
%F A336950 a(0) = 1; a(n) = Sum_{k=1..n} binomial(n,k) * k * 2^(k-1) * a(n-k).
%F A336950 a(n) ~ n! * (2/LambertW(2))^n / (1 + LambertW(2)). - _Vaclav Kotesovec_, Aug 09 2021
%t A336950 nmax = 19; CoefficientList[Series[1/(1 - x Exp[2 x]), {x, 0, nmax}], x] Range[0, nmax]!
%t A336950 Join[{1}, Table[n! Sum[(2 (n - k))^k/k!, {k, 0, n}], {n, 1, 19}]]
%t A336950 a[0] = 1; a[n_] := a[n] = Sum[Binomial[n, k] k 2^(k - 1) a[n - k], {k, 1, n}]; Table[a[n], {n, 0, 19}]
%o A336950 (PARI) seq(n)={ Vec(serlaplace(1 / (1 - x*exp(2*x + O(x^n))))) } \\ _Andrew Howroyd_, Aug 08 2020
%Y A336950 Column k=2 of A351790.
%Y A336950 Cf. A001787, A006153, A122704, A216794, A235328, A336947, A336951, A336952.
%K A336950 nonn
%O A336950 0,3
%A A336950 _Ilya Gutkovskiy_, Aug 08 2020