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 A302663 #8 Apr 11 2018 16:23:01 %S A302663 1,2,4,7,3,8,14,21,13,22,11,33,66,110,55,121,44,132,231,130,19,140,9, %T A302663 150,301,462,291,472,281,483,271,493,261,503,251,513,241,523,815,512, %U A302663 199,522,189,532,179,542,169,552,159,563,149,573,139,583,129,593,119,603,109,614,99,624,89,634,79,644 %N A302663 Lexicographically first sequence of distinct terms such that the absolute differences |a(n) - a(n+1)| are A002113(n+1), where A002113 is "the palindromes in base 10". %C A302663 The sequence starts with a(1) = 1 and is always extended with the smallest integer not yet present that doesn't lead to a contradiction. %H A302663 Jean-Marc Falcoz, <a href="/A302663/b302663.txt">Table of n, a(n) for n = 1..2229</a> %e A302663 |1 - 2| = 1, which is the 2nd palindrome of A002113 (the 1st one being "0"); %e A302663 |2 - 4| = 2 which is the 3rd palindrome; %e A302663 |4 - 7| = 3 which is the 4th palindrome; %e A302663 |7 - 3| = 4 which is the 5th palindrome; %e A302663 |3 - 8| = 5 which is the 6th palindrome; %e A302663 |8 - 14| = 6 which is the 7th palindrome; %e A302663 |14 - 21| = 7 which is the 8th palindrome; %e A302663 |21 - 13| = 8 which is the 9th palindrome; %e A302663 |13 - 22| = 9 which is the 10th palindrome; %e A302663 |22 - 11| = 11 which is the 11th palindrome; %e A302663 |11 - 33| = 22 which is the 12th palindrome; etc. %Y A302663 Cf. A002113 (palindromes in base 10). %K A302663 nonn,base %O A302663 1,2 %A A302663 _Eric Angelini_ and _Jean-Marc Falcoz_, Apr 11 2018