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 A085241 #3 Mar 30 2012 18:50:36 %S A085241 1,-1,0,1,-1,1,-1,0,1,-1,1,-1,0,1,-1,0,1,-1,1,-1,0,1,-1,1,-1,0,1,-1,0, %T A085241 1,-1,1,-1,0,1,-1,1,-1,0,1,-1,1,-1,0,1,-1,0,1,-1,1,-1,0,1,-1,1,-1,0,1, %U A085241 -1,0,1,-1,1,-1,0,1,-1,1,-1,0,1,-1,1,-1,0,1,-1,0,1,-1,1,-1,0,1 %N A085241 a(n) = A085239(n+1) - A085239(n). %K A085241 sign %O A085241 1,1 %A A085241 _Reinhard Zumkeller_, Jun 22 2003