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 A043263 #4 Mar 30 2012 18:56:34 %S A043263 0,1,2,3,2,4,6,2,3,4,5,4,5,6,7,6,7,8,9,2,4,6,8,4,6,8,10,6,8,10,12,2,3, %T A043263 4,5,4,5,6,7,6,7,8,9,8,9,10,11,4,5,6,7,6,7,8,9,8,9,10,11,10,11,12,13, %U A043263 6,7,8,9,8,9,10,11,10,11,12,13,12,13,14,15,2,4 %N A043263 Sum of the digits of the n-th base 4 palindrome. %Y A043263 A014192 (base 4 palindromes) %K A043263 nonn,base %O A043263 1,3 %A A043263 _Clark Kimberling_