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 A118520 #11 Jul 18 2015 11:27:21
%S A118520 5,8,11,14,44,47,77,80,11,14,44,47,77,80,11,14,44,47,77,80,11,14,44,
%T A118520 47,77,80,11,14,44,47,77,80,11,14,44,47,77,80,11,14,44,47,77,80,11,14,
%U A118520 44,47,77,80,11,14,44,47,77,80,11,14,44,47,77,80,11,14,44,47,77,80
%N A118520 Define sequence S_m by: initial term = m, reverse digits and add 3 to get next term. Entry shows S_5. This reaches a cycle of length 6 in 2 steps.
%H A118520 N. J. A. Sloane and others, <a href="/wiki/Sequences_of_RADD_type">Sequences of RADD type</a>, OEIS wiki.
%H A118520 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (0, 0, 0, 0, 0, 1).
%F A118520 a(n) = A118518(n+1). - _R. J. Mathar_, Sep 02 2013
%t A118520 Join[{5,8},LinearRecurrence[{0,0,0,0,0,1},{11,14,44,47,77,80},66]] (* _Ray Chandler_, Jul 18 2015 *)
%Y A118520 Cf. A117831, A118517 on.
%K A118520 nonn,base
%O A118520 1,1
%A A118520 _N. J. A. Sloane_, May 06 2006