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 A033670 #19 Jul 08 2025 19:55:42 %S A033670 89,187,968,1837,9218,17347,91718,173437,907808,1716517,8872688, %T A033670 17735476,85189247,159487405,664272356,1317544822,3602001953, %U A033670 7193004016,13297007933,47267087164,93445163438 %N A033670 Trajectory of 89 under map x->x + (x-with-digits-reversed). %C A033670 The sequence reaches a palindrome at a(24)= 8813200023188 (cf. A033665). - _Klaus Brockhaus_, Jun 07 2002 %D A033670 Popular Computing (Calabasas, CA), The 196 Problem, Vol. 3 (No. 30, Sep 1975), page PC30-6. Gives full 25-term trajectory of 89. %H A033670 Vincenzo Librandi, <a href="/A033670/b033670.txt">Table of n, a(n) for n = 0..1000</a> %H A033670 Jason Doucette, <a href="http://www.jasondoucette.com/worldrecords.html#Most">World Records</a> %H A033670 I. Peter, <a href="http://www.floot.demon.co.uk/palindromes.html">More trajectories</a> %H A033670 <a href="/index/Res#RAA">Index entries for sequences related to Reverse and Add!</a> %e A033670 a(3) = 968 because 187 + 781 = 968 %t A033670 NestList[# + FromDigits[Reverse[IntegerDigits[#]]]&, 89, 40] (* _Vincenzo Librandi_, May 03 2014 *) %K A033670 nonn,base %O A033670 0,1 %A A033670 _N. J. A. Sloane_