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 A072784 #2 May 01 2014 02:47:42 %S A072784 0,0,-1,0,1,-1,0,0,1,-1,0,0,0,1,-1,0,0,0,-1,1,-1,0,0,0,1,-1,1,-1,0,0, %T A072784 0,0,1,-1,1,-1,0,0,0,0,0,1,-1,1,-1,0,0,0,0,0,-1,1,-1,1,-1,0,0,0,0,0,1, %U A072784 -1,1,-1,1,-1,0,0,0,0,0,0,1,-1,1,-1,1,-1,0,0,0,0,0,0,0,1,-1,1,-1,1,-1,0,0,0,0,0,0,0,-1,1,-1,1,-1,1,-1,0,0,0,0,0,0,0,1 %N A072784 Differences between A072741 and A072737. %o A072784 (Scheme) (define (A072784 n) (- (A072741 n) (A072737 n))) %K A072784 sign,tabl %O A072784 0,1 %A A072784 _Antti Karttunen_, Jun 12 2002