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 A136731 #2 Mar 30 2012 18:37:09 %S A136731 1,2,5,23,175,1935,28432,523290,11587072,299942890,8886126540, %T A136731 296438370794,10993731095695,448604373236731,19971257117211555, %U A136731 963142501803505255,50015707804752012825,2782336529985704607295 %N A136731 Column 1 of square array A136730. %Y A136731 Cf. A136730; A101482, A136732. %K A136731 nonn %O A136731 0,2 %A A136731 _Paul D. Hanna_, Jan 19 2008