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 A117800 #12 Aug 27 2024 16:51:21 %S A117800 1,6,11,16,66,71,22,27,77,82,33,38,88,93,44,49,99,104,406,609,911,124, %T A117800 426,629,931,144,446,649,951,164,466,669,971,184,486,689,991,204,407, %U A117800 709,912,224,427,729,932,244,447,749,952,264,467,769,972,284,487,789,992,304,408 %N A117800 Start with 1 and repeatedly reverse the digits and add 5 to get the next term. %H A117800 N. J. A. Sloane, <a href="/A117800/b117800.txt">Table of n, a(n) for n = 0..414</a> (shows two full cycles) %H A117800 N. J. A. Sloane and others, <a href="/wiki/Sequences_of_RADD_type">Sequences of RADD type</a>, OEIS wiki. %H A117800 <a href="/index/Rec#order_207">Index entries for linear recurrences with constant coefficients</a>, order 207. %F A117800 After 1 step enters a cycle of length 207. %F A117800 It appears that there is a unique cycle of length 207 for the reverse-and-add-5 problem. Klaus Brockhaus has done an extensive search without finding any further cycle of length 207. There are many cycles of lengths 36 and 756. See A118878. %t A117800 NestList[IntegerReverse[#] + 5 &, 1, 100] (* _Paolo Xausa_, Aug 27 2024 *) %Y A117800 Cf. A117828, A118878, A118879. %K A117800 nonn,base %O A117800 0,2 %A A117800 _N. J. A. Sloane_, following discussions with Luc Stevens, May 04 2006