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 A169939 #4 Mar 30 2012 16:51:46 %S A169939 0,1,3,10,11,13,30,31,100,101,103,110,111,113,130,300,301,310,311, %T A169939 1000,1001,1003,1010,1011,1013,1030,1031,1100,1101,1103,1110,1111, %U A169939 1113,1130,1300,1301,3000,3001,3010,3011,3100,3101,3110,3111,10000,10001,10003,10010 %N A169939 Skinny numbers (A061909) containing no 2's. %H A169939 <a href="/index/Ca#CARRYLESS">Index entries for sequences related to carryless arithmetic</a> %K A169939 nonn,base %O A169939 1,3 %A A169939 _N. J. A. Sloane_, Jul 29 2010