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 A004289 #6 Mar 30 2012 18:35:05 %S A004289 1,11,10,1111,11,110,111,11111111,10,11,11111,11110,111,111111,110, %T A004289 101111111,10001,110,11101,1111,1110,110101,11001,111111110,11011, %U A004289 111111,100,1001101,100101,110,111001,111011111,111110,10001,111111 %N A004289 Least positive multiple of n written in base 9 using only 0 and 1. %K A004289 nonn,base %O A004289 1,2 %A A004289 _David W. Wilson_