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 A120787 #3 Mar 31 2012 13:20:12 %S A120787 1,20,200,1600,80000,1600000,16000000,1280000000,2560000000, %T A120787 256000000000,2560000000000,102400000000000,1024000000000000, %U A120787 4096000000000000,40960000000000000,6553600000000000000 %N A120787 Denominators of partial sums of Catalan numbers scaled by powers of 1/20. %C A120787 Numerators are given under A120786. %F A120787 a(n)=denominator(r(n)), with the rationals r(n):=sum(C(k)/20^k,k=0..n) with C(k):=A000108(k) (Catalan numbers). %K A120787 nonn,easy,frac %O A120787 0,2 %A A120787 _Wolfdieter Lang_, Jul 20 2006