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 A109572 #5 Jun 26 2013 10:50:10
%S A109572 0,1,2,6,32,200,1536,13664,139264,1595520,20316160,284534272,
%T A109572 4347396096,71958415360,1282685272064,24497477345280,499058556796928,
%U A109572 10802158189445120,247567232110952448,5989035387568652288
%N A109572 E.g.f.: x/[1-tan(x)].
%C A109572 "Bernoulli numbers" for x/[1-tan(x)].
%F A109572 a(n) ~ n! * 2^(2*n-1)/Pi^n. - _Vaclav Kotesovec_, Jun 26 2013
%p A109572 G:=x/(1-tan(x)): Gser:=series(G,x=0,25): 0,seq(n!*coeff(Gser,x^n),n=1..22);
%t A109572 g[x_] = x/(-1 + Tan[x]) h[x_, n_] = Dt[g[x], {x, n}] a[x_] = Table[ -h[x, n], {n, 0, 50}]; b = a[0]
%Y A109572 Cf. A057711.
%K A109572 nonn
%O A109572 0,3
%A A109572 _Roger L. Bagula_, Jun 27 2005