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 A012063 #10 Nov 21 2013 12:46:00
%S A012063 1,1,1,3,9,49,249,1963,14129,146017,1362961,17450227,200409465,
%T A012063 3064381137,41812246345,744091967643,11765081428705,239039270010305,
%U A012063 4298599985014945,98237724213189475,1980239469431883625
%N A012063 exp(arcsin(arcsin(x)))=1+x+1/2!*x^2+3/3!*x^3+9/4!*x^4+49/5!*x^5...
%t A012063 With[{nn=30},CoefficientList[Series[Exp[ArcSin[ArcSin[x]]],{x,0,nn}], x]Range[0,nn]!] (* _Harvey P. Dale_, Jan 04 2012 *)
%K A012063 nonn
%O A012063 0,4
%A A012063 Patrick Demichel (patrick.demichel(AT)hp.com)
%E A012063 Confirmed by _N. J. A. Sloane_, Dec 17 2011