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 A033660 #18 Jul 08 2025 19:55:21 %S A033660 29,121,242,484,968,1837,9218,17347,91718,173437,907808,1716517, %T A033660 8872688,17735476,85189247,159487405,664272356,1317544822,3602001953, %U A033660 7193004016,13297007933,47267087164 %N A033660 Trajectory of 29 under map x->x + (x-with-digits-reversed). %H A033660 Harvey P. Dale, <a href="/A033660/b033660.txt">Table of n, a(n) for n = 0..1000</a> %H A033660 <a href="/index/Res#RAA">Index entries for sequences related to Reverse and Add!</a> %F A033660 a(n)=A033655(n+1), n>0. [From _R. J. Mathar_, Oct 22 2008] %t A033660 NestList[#+IntegerReverse[#]&,29,30] (* _Harvey P. Dale_, Apr 13 2019 *) %K A033660 nonn,base %O A033660 0,1 %A A033660 _N. J. A. Sloane_