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 A362604 #50 Feb 16 2025 08:34:05
%S A362604 1,1,4,33,352,4805,80256,1582693,36001792,927974601,26729943040,
%T A362604 850921057481,29666297020416,1124166449205709,46005243970846720,
%U A362604 2022121401647311245,95008417631810093056,4751844218849365365137,252063937292253895065600
%N A362604 Expansion of e.g.f. 1/(1 + LambertW(-x * exp(x^2))).
%H A362604 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/LambertW-Function.html">Lambert W-Function</a>.
%F A362604 a(n) = n! * Sum_{k=0..floor(n/2)} (n-2*k)^(n-k) / (k! * (n-2*k)!).
%o A362604 (PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace(1/(1+lambertw(-x*exp(x^2)))))
%Y A362604 Cf. A072034, A362699.
%Y A362604 Cf. A216688, A356834, A362700, A362702.
%K A362604 nonn,easy
%O A362604 0,3
%A A362604 _Seiichi Manyama_, Apr 30 2023