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 A119939 #2 Mar 31 2012 13:20:12 %S A119939 3,5,7,81,44,1300,3375,20825,14896,1333584,1014300,133402500, %T A119939 105850800,85395024,279558279,66958716825,56112056000,17143034708800, %U A119939 14636445039216,12595733648784,10917487339200,5038547354568000 %N A119939 Main diagonal of triangle A119937. %F A119939 a(n)= A119937(m,m-1), m>=2. %K A119939 nonn,easy %O A119939 2,1 %A A119939 _Wolfdieter Lang_, Jul 20 2006