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 A027159 #4 Mar 30 2012 18:56:14 %S A027159 3,10,76,264,2208,7744,67776,238720,2144768,7572480,69203968, %T A027159 244715520,2263351296,8012201984,74764042240,264873738240, %U A027159 2488551997440,8821831106560,83334108020736,295559851147264,2804309838266368 %N A027159 a(n) = T(2n,n-1), T given by A027157. %K A027159 nonn %O A027159 1,1 %A A027159 _Clark Kimberling_