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 A277510 #19 Jun 02 2019 05:38:30
%S A277510 -1,2,-2,6,8,170,1872,29246,519808,10698642,248787200,6458737142,
%T A277510 185138721792,5808233422394,197952647108608,7283047491096750,
%U A277510 287705410381709312,12145740050403520034,545696709922799419392,25998534614835587104742,1309210567403228200960000
%N A277510 E.g.f.: -1/(1-LambertW(-x))^2.
%H A277510 G. C. Greubel, <a href="/A277510/b277510.txt">Table of n, a(n) for n = 0..385</a>
%F A277510 a(n) ~ n^(n-1) / 4.
%t A277510 CoefficientList[Series[-1/(1-LambertW[-x])^2, {x, 0, 20}], x] * Range[0, 20]!
%o A277510 (PARI) x='x+O('x^50); Vec(serlaplace(-1/(1 - lambertw(-x))^2)) \\ _G. C. Greubel_, Nov 08 2017
%Y A277510 Cf. A063170, A134095, A277458, A277490, A308506.
%K A277510 sign
%O A277510 0,2
%A A277510 _Vaclav Kotesovec_, Oct 18 2016