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 A043275 #4 Mar 30 2012 18:56:34 %S A043275 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,2,4,6,8,10,12,14,16,18,20,22, %T A043275 24,26,28,30,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,4,5,6,7,8,9,10, %U A043275 11,12,13,14,15,16,17,18,19,6,7,8,9,10,11,12,13 %N A043275 Sum of the digits of the n-th base 16 palindrome. %Y A043275 A029730 (base 16 palindromes) %K A043275 nonn,base %O A043275 1,3 %A A043275 _Clark Kimberling_