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 A027161 #4 Mar 30 2012 18:56:14 %S A027161 2,6,40,152,1088,4416,32384,135552,1006592,4289536,32100352,138407936, %T A027161 1041203200,4526702592,34182430720,149528084480,1132376883200, %U A027161 4977103994880,37776580935680,166668216041472,1267318675996672 %N A027161 T(2n-1,n-1), T given by A027157. %K A027161 nonn %O A027161 1,1 %A A027161 _Clark Kimberling_