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 A054140 #4 Mar 30 2012 18:57:03 %S A054140 1,9,46,264,1602,9981,63068,402058,2579386,16629321,107637426, %T A054140 699032274,4552606344,29722287276,194458646688 %N A054140 T(2n+1,n), array T as in A054134. %K A054140 nonn %O A054140 0,2 %A A054140 _Clark Kimberling_