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 A055648 #3 Mar 30 2012 18:51:26 %S A055648 0,1,2,3,4,5,6,7,8,9,10,11,12,100,101,102,103,104,105,106,107,108,109, %T A055648 110,111,112,200,201,202,203,204,205,206,207,208,209,210,211,212,300, %U A055648 301,302,303,304,305,306,307,308,309,310,311,312,400,401,402,403,404 %N A055648 Integers in base 13 with each base 13 digit represented by 2 decimal digits. %Y A055648 Cf. A049872. %K A055648 base,easy,nonn %O A055648 0,3 %A A055648 _Henry Bottomley_, Jun 06 2000