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 A236357 #4 Jan 23 2014 08:23:46
%S A236357 -1,2,-12,120,-1680,30360,-672000,17599680,-532224000,18248902560,
%T A236357 -699544581120,29645099003520,-1376154991411200,69445751181206400,
%U A236357 -3785191236642816000,221613328121888102400,-13870531255760776396800,924194452386724174656000
%N A236357 E.g.f. satisfies: sin(x + A(x)) = A(x)^2.
%C A236357 For n < 10 is |a(n)| = A215188(n), but a(10) is different.
%F A236357 E.g.f.: Series_Reversion(arcsin(x^2)-x).
%F A236357 a(n) ~ (-1)^n * (4/sqrt(5)-8/5)^(1/4) * n^(n-1) / (exp(n) * (sqrt(sqrt(5)-2) - arcsin(sqrt(5)-2))^(n-1/2))
%t A236357 Rest[CoefficientList[InverseSeries[Series[ArcSin[x^2]-x,{x,0,20}],x],x] * Range[0,20]!]
%Y A236357 Cf. A215188, A143135.
%K A236357 sign
%O A236357 1,2
%A A236357 _Vaclav Kotesovec_, Jan 23 2014