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 A277484 #11 Nov 09 2017 03:14:23
%S A277484 0,0,2,6,32,300,3624,52570,908928,18277560,417634080,10682763278,
%T A277484 302517156864,9394763009060,317429118686848,11592017133950370,
%U A277484 454961391572119552,19097430979664893168,853711115246721262080,40490675416206345889686,2030782746261324446228480
%N A277484 E.g.f.: -arcsinh(x)*LambertW(-x).
%H A277484 G. C. Greubel, <a href="/A277484/b277484.txt">Table of n, a(n) for n = 0..385</a>
%F A277484 a(n) ~ arcsinh(exp(-1)) * n^(n-1).
%F A277484 a(n) ~ (-1 + log(1 + sqrt(1+exp(2)))) * n^(n-1).
%t A277484 CoefficientList[Series[-ArcSinh[x]*LambertW[-x], {x, 0, 20}], x] * Range[0, 20]!
%t A277484 Flatten[{0, Table[Sum[Sin[Pi*k/2] * Binomial[n, k] * (k-2)!!^2 * (n-k)^(n-k-1), {k, 1, n-1}], {n, 1, 20}]}] (* _Vaclav Kotesovec_, Oct 28 2016 *)
%o A277484 (PARI) x='x+O('x^10); concat([0,0], Vec(serlaplace(-asinh(x)*lambertw(-x) ))) \\ _G. C. Greubel_, Nov 08 2017
%Y A277484 Cf. A000169, A277470, A277473, A277483.
%K A277484 nonn
%O A277484 0,3
%A A277484 _Vaclav Kotesovec_, Oct 17 2016