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 A118634 #6 Jul 20 2015 11:28:36 %S A118634 1,39,131,169,999,1037,7339,9375,5777,7813,3225,5261,1663,3699,10001, %T A118634 10039,93039,93077,77077,77115,51215,51253,35253,35291,19291,19329, %U A118634 92429,92467,76467,76505,50605,50643,34643,34681,18681,18719,91819 %N A118634 Start with 1 and repeatedly reverse the digits and add 38 to get the next term. %C A118634 After 122 steps enters a cycle of length 18. Cycle is 95, 97, 117, 749, 985, 627, 764, 505, 543, 383, 421, 162, 299, 1030, 339, 971, 217, 750, 95,... %H A118634 N. J. A. Sloane and others, <a href="/wiki/Sequences_of_RADD_type">Sequences of RADD type</a>, OEIS wiki. %H A118634 <a href="/index/Rec#order_18">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, 1). %Y A118634 Cf. A117828, A117816, A117817. %K A118634 base,nonn %O A118634 1,2 %A A118634 Luc Stevens (lms022(AT)yahoo.com), May 09 2006