A318533 - OEIS

%I #8 Sep 04 2018 15:14:09

%S 1,2,3,4,5,6,10,13,9,20,21,14,8,15,7,16,60,61,50,51,40,41,30,31,24,90,

%T 91,80,81,70,71,62,42,25,82,63,32,17,52,35,92,72,53,26,73,43,18,46,93,

%U 64,27,65,19,36,83,54,100,102,94,57,95,47,84,48,74,37,75,28,58,85,38,68,96,39,59,76,103,86,29,49,69,87,104

%N Lexicographically first sequence of distinct positive integers such that a(n) + [the first digit of a(n+1)] is a palindrome in base 10.

%H Jean-Marc Falcoz, <a href="/A318533/b318533.txt">Table of n, a(n) for n = 1..10001</a>

%e The sequence starts with 1,2,3,4,5,6,10,13,9,... and we see that [1 + (the first digit of 2)] is a palindrome (3); [2 + (the first digit of 3)] is a palindrome (5); [3 + (the first digit of 4)] is a palindrome (7); [4 + (the first digit of 5)] is a palindrome (9); [5 + (the first digit of 6)] is a palindrome (11); [6 + (the first digit of 10)] is a palindrome (7); [10 + (the first digit of 13)] is a palindrome (11); [13 + (the first digit of 9)] is a palindrome (22); etc.

%Y Cf. A318486 for a subtraction of the first digit of a(n+1) instead of the addition.

%K nonn,base,look

%O 1,2

%A _Eric Angelini_ and _Jean-Marc Falcoz_, Aug 28 2018