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 A337865 #15 Sep 30 2020 14:56:35 %S A337865 1,2,3,4,5,6,17,28,37,7,18,38,16,27,47,8,19,29,51,62,73,82,71,102,9, %T A337865 31,42,53,64,74,41,52,63,83,61,72,92,91,111,101,121,131,141,151,15,26, %U A337865 57,13,24,35,46,55,11,22,33,44,75,65,21,32,43,54,76,56,12,23,34,45,66 %N A337865 Lexicographically earliest sequence of distinct positive integers such that the sum of a(n) and [a(n+1) reversed] is a palindrome in base 10. %C A337865 Terms ending in zero are not in the sequence; when reversed they produce a term with a leading zero. %H A337865 Carole Dubois, <a href="/A337865/b337865.txt">Table of n, a(n) for n = 1..5001</a> %e A337865 a(7) = 17 and a(8) = 28; the addition 17 + 82 is a palindrome (99). %e A337865 a(8) = 28 and a(9) = 37; the addition 28 + 73 is a palindrome (101). Etc. %Y A337865 Cf. A228730 (the sum of two consecutive terms is a palindrome in base 10). %K A337865 nonn,base,look %O A337865 1,2 %A A337865 _Eric Angelini_ and _Carole Dubois_, Sep 27 2020