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 A362858 #12 Feb 16 2025 08:34:05
%S A362858 1,-2,7,-9,121,797,14517,251521,5199313,120881133,3139282909,
%T A362858 90010844657,2824532243001,96284834673349,3543187673495269,
%U A362858 139992580020525993,5910844405813258273,265606657711863337181,12655895981349401656749
%N A362858 Expansion of e.g.f. exp(-3*x) / (1 + LambertW(-x)).
%H A362858 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/LambertW-Function.html">Lambert W-Function</a>.
%F A362858 G.f.: Sum_{k>=0} (k*x)^k / (1 + 3*x)^(k+1).
%F A362858 a(n) = Sum_{k=0..n} (-3)^(n-k) * k^k * binomial(n,k).
%o A362858 (PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace(exp(-3*x)/(1 + lambertw(-x))))
%Y A362858 Column k=3 of A362856.
%Y A362858 Cf. A362860.
%K A362858 sign
%O A362858 0,2
%A A362858 _Seiichi Manyama_, May 05 2023