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 A117829 #19 Feb 17 2025 15:08:48 %S A117829 3,7,11,15,55,59,99,103,305,507,709,911,123,325,527,729,931,143,345, %T A117829 547,749,951,163,365,567,769,971,183,385,587,789,991,203,306,607,710, %U A117829 21,16,65,60,10,5,9,13,35,57,79,101,105,505,509,909,913,323,327,727,731,141,145 %N A117829 Start with 3 and repeatedly reverse the digits and add 4 to get the next term. %H A117829 Harvey P. Dale, <a href="/A117829/b117829.txt">Table of n, a(n) for n = 1..1000</a> %H A117829 N. J. A. Sloane and others, <a href="/wiki/Sequences_of_RADD_type">Sequences of RADD type</a>, OEIS wiki. %H A117829 <a href="/index/Rec#order_54">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, 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 A117829 Has period 54: see A117827, A117830. %p A117829 read transforms; t1:=[3]; for n from 1 to 80 do t1:=[op(t1),4+digrev(t1[n])]; od: # _N. J. A. Sloane_ %t A117829 f[n_] := 4 + FromDigits@ Reverse@ IntegerDigits@n; NestList[ f@# &, 3, 58] (* _James C. McMahon_, Sep 24 2024 *) %t A117829 NestList[IntegerReverse[#]+4&,3,60] (* _Harvey P. Dale_, Feb 17 2025 *) %Y A117829 Cf. A117827, A117828, A117830. %K A117829 nonn,base %O A117829 1,1 %A A117829 Luc Stevens (lms022(AT)yahoo.com), Apr 06 2006