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 A012723 #4 Feb 24 2012 12:51:06 %S A012723 1,2,24,718,40040,3586122,470928612,85257985902,20354196606768, %T A012723 6195953068191762,2342416197502447932,1076777305129376444790, %U A012723 591474826398069745456200,382625479333794154176056730 %N A012723 exp(arctanh(x)*arcsin(x))=1+2/2!*x^2+24/4!*x^4+718/6!*x^6+40040/8!*x^8... %K A012723 nonn %O A012723 0,2 %A A012723 Patrick Demichel (patrick.demichel(AT)hp.com)