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 A043272 #6 May 08 2020 14:06:48 %S A043272 0,1,2,3,4,5,6,7,8,9,10,11,12,2,4,6,8,10,12,14,16,18,20,22,24,2,3,4,5, %T A043272 6,7,8,9,10,11,12,13,14,4,5,6,7,8,9,10,11,12,13,14,15,16,6,7,8,9,10, %U A043272 11,12,13,14,15,16,17,18,8,9,10,11,12,13,14,15 %N A043272 Sum of the digits of the n-th base 13 palindrome. %t A043272 Total[IntegerDigits[#,13]]&/@Select[Range[0,1000],IntegerDigits[#,13] == Reverse[ IntegerDigits[ #,13]]&] (* _Harvey P. Dale_, May 08 2020 *) %Y A043272 A029958 (base 13 palindromes) %K A043272 nonn,base %O A043272 1,3 %A A043272 _Clark Kimberling_