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 A033674 #16 Jul 08 2025 19:56:04 %S A033674 99,198,1089,10890,20691,40293,79497,158994,658845,1207701,2284722, %T A033674 4559544,9019098,17928207,88211178,175322466,839546037,1570191975, %U A033674 7362102726,13634115363,49985258994,99970517988 %N A033674 Trajectory of 99 under map x->x + (x-with-digits-reversed). %H A033674 <a href="/index/Res#RAA">Index entries for sequences related to Reverse and Add!</a> %F A033674 a(n)=A033659(n+1). [From _R. J. Mathar_, Oct 22 2008] %t A033674 NestList[IntegerReverse[#]+#&,99,30] (* The program uses the IntegerReverse function from Mathematica version 10 *) (* _Harvey P. Dale_, Dec 05 2015 *) %K A033674 nonn,base %O A033674 0,1 %A A033674 _N. J. A. Sloane_