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 A118525 #20 Jul 19 2015 19:43:02
%S A118525 1,7,13,37,79,103,307,709,913,325,529,931,145,547,751,163,367,769,973,
%T A118525 385,589,991,205,508,811,124,427,730,43,40,10,7,13,37,79,103,307,709,
%U A118525 913,325,529,931,145,547,751,163,367,769,973,385,589,991
%N A118525 Start with 1 and repeatedly reverse the digits and add 6 to get the next term.
%C A118525 After the initial term, the sequence enters the cycle (7, 13, 37, ..., 10) of length 30.
%H A118525 N. J. A. Sloane and others, <a href="/wiki/Sequences_of_RADD_type">Sequences of RADD type</a>, OEIS wiki.
%H A118525 <a href="/index/Rec#order_30">Index entries for linear recurrences with constant coefficients</a>, signature (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1).
%F A118525 a(n) = a((n-2 mod 30)+2) for all n>1. - _M. F. Hasler_, May 22 2014
%t A118525 NestList[FromDigits[Reverse[IntegerDigits[#]]]+6&,1,60] (* _Harvey P. Dale_, Apr 22 2011 *)
%o A118525 (PARI) a(n,s=1)={n>1&&for(i=0,(n-2)%30,s=R(s)+6);s} \\ R = A004086. - _M. F. Hasler_, May 22 2014
%Y A118525 Cf. A117828, A117816, A117817.
%K A118525 nonn,base
%O A118525 1,2
%A A118525 _N. J. A. Sloane_, May 06 2006