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 A109967 #5 Jan 04 2013 16:19:37 %S A109967 0,1,0,1,1,1,1,2,1,2,2,1,3,2,2,2,3,1,3,2,2,2,1,2,1,2,0,2,0,1,0,2,0,0, %T A109967 2,-1,2,0,2,0,3,0,3,2,0,4,1,3,1,4,0,4,1,4,2,0,4,0,4,0,4,0,4,0,5,2,0,6, %U A109967 0,5,1,6,0,7,1,7,4,0,8,1,7,1,8,0,8,1,8,4,0,9,0,8,0,9,-1,9,0,10,4,-1,11,-1 %N A109967 First differences of A088670. %C A109967 a(n) = A088670(n+1) - A088670(n). %Y A109967 Cf. A109969. %K A109967 sign,base %O A109967 1,8 %A A109967 _Reinhard Zumkeller_, Jul 06 2005