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 A043266 #4 Mar 30 2012 18:56:34 %S A043266 0,1,2,3,4,5,6,2,4,6,8,10,12,2,3,4,5,6,7,8,4,5,6,7,8,9,10,6,7,8,9,10, %T A043266 11,12,8,9,10,11,12,13,14,10,11,12,13,14,15,16,12,13,14,15,16,17,18,2, %U A043266 4,6,8,10,12,14,4,6,8,10,12,14,16,6,8,10,12,14 %N A043266 Sum of the digits of the n-th base 7 palindrome. %Y A043266 A029954 (base 7 palindromes) %K A043266 nonn,base %O A043266 1,3 %A A043266 _Clark Kimberling_