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 A127636 #2 Mar 30 2012 18:59:19 %S A127636 1,6,99,4590,601749,223671780,236051526780,707876792166456, %T A127636 6035175245831686020,146337688589606021286324, %U A127636 10094030504239191283895044707,1981045079056219549583047340549844 %N A127636 Hankel transform of C(3n,n), A005809. %F A127636 a(n)=3^n*A051255(n). %K A127636 nonn %O A127636 0,2 %A A127636 _Paul Barry_, Jan 21 2007