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 A098161 #3 Mar 31 2012 13:46:50 %S A098161 0,2,3,5,6,8,9,10,21,30,41,50,61,70,81,90,211,221,300,310,411,421,500, %T A098161 510,611,621,700,710,811,821,900,910,2110,2112,2114,2116,2118,2130, %U A098161 2132,2134,2136,2138,2150,2152,2154,2156,2158,2170,2172,2174,2176,2178,2190 %N A098161 Slowest increasing sequence where the digits fit the infinite repeating pattern even/even/odd/odd/even/even/odd/odd/... %K A098161 base,easy,nonn %O A098161 0,2 %A A098161 _Eric Angelini_, Oct 25 2004 %E A098161 Corrected and extended by _Robert G. Wilson v_, Oct 25 2004