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 A139543 #2 Mar 31 2012 10:29:25 %S A139543 3,93,402,2846,28242,826393 %N A139543 First n digits of 10^n!. %K A139543 nonn,base,less %O A139543 1,1 %A A139543 _Jeff Burch_, Jun 10 2008