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 A115236 #3 Mar 30 2012 17:37:16 %S A115236 1,-1,1,1,-2,1,-1,2,-2,1,0,0,1,-2,1,1,-2,1,1,-2,1,0,0,0,0,1,-2,1,-1,2, %T A115236 -2,1,0,1,-2,1,0,0,0,0,0,0,1,-2,1,0,0,1,-2,1,0,0,1,-2,1,0,0,0,0,0,0,0, %U A115236 0,1,-2,1,1,-2,1,1,-2,1,0,0,0,1,-2,1,0,0,0,0,0,0,0,0,0,0,1,-2,1,0,0,0 %N A115236 Matrix inverse of triangle A003983. %e A115236 1; -1,1; 1,-2,1; -1,2,-2,1; 0,0,1,-2,1; ... %K A115236 sign,tabl %O A115236 0,5 %A A115236 _Christian G. Bower_, Jan 17 2006