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 A127112 #2 Mar 31 2012 10:22:03
%S A127112 1,1,2,12,120,1320,23100,1032300,21312000,1120212000,31311330000,
%T A127112 2120101110000,130203033300000,11303022030300000,1101030032302200000,
%U A127112 103001313131311200000
%N A127112 n! in base 4.
%t A127112 b = Table[IntegerDigits[n!, 4], {n, 1, 15}]; a = {}; Do[AppendTo[a, FromDigits[b[[x]]]], {x, 1, Length[b]}]; a (*Artur Jasinski*)
%K A127112 nonn
%O A127112 0,3
%A A127112 _Artur Jasinski_, Jan 05 2007