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 A043060 #5 Jul 12 2012 00:39:46 %S A043060 1,3,15,16,17,18,19,20,21,99,107,115,123,131,139,147,687,694,701,708, %T A043060 715,722,729,737,744,751,758,765,772,779,787,794,801,808,815,822,829, %U A043060 837,844,851,858,865,872,879,887,894,901,908 %N A043060 a(n)=(s(n)+5)/7, where s(n)=n-th base 7 palindrome that starts with 2. %K A043060 nonn,base %O A043060 1,2 %A A043060 _Clark Kimberling_