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 A027158 #4 Mar 30 2012 18:56:14 %S A027158 1,3,24,76,672,2208,20224,67776,632320,2144768,20238336,69203968, %T A027158 658079744,2263351296,21643526144,74764042240,717975060480, %U A027158 2488551997440,23977645834240,83334108020736,805090608807936,2804309838266368 %N A027158 a(n) = T(2n,n), T given by A027157. %K A027158 nonn %O A027158 0,2 %A A027158 _Clark Kimberling_