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 A118607 #14 Feb 19 2023 11:01:52
%S A118607 1,19,109,919,937,757,775,595,613,334,451,172,289,1000,19,109,919,937,
%T A118607 757,775,595,613,334,451,172,289,1000,19,109,919,937,757,775,595,613,
%U A118607 334,451,172,289,1000,19,109,919,937,757,775,595,613,334,451,172,289
%N A118607 Start with 1 and repeatedly reverse the digits and add 18 to get the next term.
%C A118607 After 1 step enters a cycle of length 13.
%H A118607 Harvey P. Dale, <a href="/A118607/b118607.txt">Table of n, a(n) for n = 1..1000</a>
%H A118607 N. J. A. Sloane and others, <a href="/wiki/Sequences_of_RADD_type">Sequences of RADD type</a>, OEIS wiki.
%H A118607 <a href="/index/Rec#order_13">Index entries for linear recurrences with constant coefficients</a>, signature (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1).
%F A118607 a(n) = a(n-13) for n >= 15. - _Wesley Ivan Hurt_, Sep 04 2022
%t A118607 NestList[IntegerReverse[#]+18&,1,60] (* or *) PadRight[{1},120,{1000,19,109,919,937,757,775,595,613,334,451,172,289}] (* _Harvey P. Dale_, Feb 19 2023 *)
%Y A118607 Cf. A117828, A117816, A117817.
%K A118607 base,nonn
%O A118607 1,2
%A A118607 Luc Stevens (lms022(AT)yahoo.com), May 08 2006