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 A012782 #4 Feb 24 2012 12:51:08 %S A012782 1,1,1,5,17,85,505,3201,25153,204905,1945265,19581949,217998673, %T A012782 2608398013,33522871785,463598293497,6789373095937,106484041306577, %U A012782 1755926841763681,30821112722260469,566210591513987345 %N A012782 exp(sec(x)*arcsin(x))=1+x+1/2!*x^2+5/3!*x^3+17/4!*x^4+85/5!*x^5... %K A012782 nonn %O A012782 0,4 %A A012782 Patrick Demichel (patrick.demichel(AT)hp.com)