%I #18 Oct 18 2019 21:34:26
%S 1,1,1,1,1,1,1,1,1,2,1,2,2,2,2,2,2,2,3,2,2,1,2,2,2,2,2,3,2,2,2,2,1,2,
%T 2,2,3,2,3,2,2,2,2,1,2,3,2,3,3,2,2,2,2,2,1,2,3,3,4,2,2,2,2,3,2,1,3,4,
%U 5,2,2,2,3,2,3,3,1,5,7,2,2,3,2,3,3,4,5,1,25,2,3,2,3,3,4,5,7,25
%N Number of terms (including the initial term) needed to reach a palindrome when the Reverse Then Add! map (x -> x + (x-with-digits-reversed)) is repeatedly applied to n, or -1 if a palindrome is never reached.
%C It is conjectured that a(196) is the smallest term equal to -1. See A023108.
%D Daniel Lignon, Dictionnaire de (presque) tous les nombres entiers, Ellipses, Paris, 2012, 702 pages. See Entry 196.
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/196-Algorithm.html">196 Algorithm.</a>
%t Table[Length@
%t NestWhileList[# + IntegerReverse[#] &, n, ! PalindromeQ[#] &], {n, 98}] (* _Robert Price_, Oct 18 2019 *)
%Y Cf. A006960, A023108, A063018, etc.
%Y Equals A033665(n) + 1.
%K nonn,base
%O 1,10
%A _Eric W. Weisstein_
%E Edited by _N. J. A. Sloane_, May 09 2015