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 A362660 #16 Aug 05 2025 06:54:00
%S A362660 1,1,3,19,161,1791,24847,413449,8036625,178852753,4486426091,
%T A362660 125279093259,3854964555697,129618443364463,4728625129171959,
%U A362660 186034319795094481,7851808690935373793,353903271319498588641,16966669198377512202643
%N A362660 E.g.f. satisfies A(x) = exp( x * exp(x^2/2) * A(x) ).
%H A362660 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/LambertW-Function.html">Lambert W-Function</a>.
%F A362660 E.g.f.: exp( -LambertW(-x * exp(x^2/2)) ).
%F A362660 a(n) = n! * Sum_{k=0..floor(n/2)} (n-2*k)^k * (n-2*k+1)^(n-2*k-1) / (2^k * k! * (n-2*k)!).
%F A362660 a(n) ~ sqrt(1 + LambertW(exp(-2))) * n^(n-1) / (exp(n-1) * LambertW(exp(-2))^(n/2)). - _Vaclav Kotesovec_, Aug 05 2025
%o A362660 (PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace(exp(-lambertw(-x*exp(x^2/2)))))
%Y A362660 Cf. A273954, A362661.
%Y A362660 Cf. A354550, A362654.
%K A362660 nonn
%O A362660 0,3
%A A362660 _Seiichi Manyama_, Apr 29 2023