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 A112003 #3 Oct 12 2012 14:40:24 %S A112003 -30,1827,-75915,2774695,-97362265,3410657250,-121647896370, %T A112003 4464233824050,-169525943987400,6681570663692925,-273715584240223125, %U A112003 11660420923428902625,-516518847915111916875,23780637468174359272500,-1137205925185934836732500 %N A112003 One fourth of fifth column (k=4) of triangle A111999. %F A112003 a(n)=A111999(n+5, 4)/4, n>=0. %K A112003 sign,easy %O A112003 0,1 %A A112003 _Wolfdieter Lang_, Sep 12 2005