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 A101233 #2 Mar 31 2012 13:46:50 %S A101233 1,11,12,22,23,33,34,44,45,55,56,66,67,77,78,88,89,91,101,111,121,131, %T A101233 141,151,161,171,181,191,192,202,212,222,232,242,252,262,272,282,292, %U A101233 293,303,313,323,333,343,353,363,373,383,393,394,404,414,424,434,444 %N A101233 Slowest increasing sequence where the absolute difference between the last digit of a(n) and the first digit of a(n+1) equals 0. %K A101233 base,easy,nonn %O A101233 1,2 %A A101233 _Eric Angelini_, Dec 16 2004