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 A135449 #24 Sep 25 2024 23:12:57 %S A135449 1,9,-7,3,5,1,9,-7,3,5,1,9,-7,3,5,1,9,-7,3,5,1,9,-7,3,5,1,9,-7,3,5,1, %T A135449 9,-7,3,5,1,9,-7,3,5,1,9,-7,3,5,1,9,-7,3,5,1,9,-7,3,5,1,9,-7,3,5,1,9, %U A135449 -7,3,5,1,9,-7,3,5,1,9,-7,3,5,1,9,-7,3,5,1,9,-7,3,5,1,9,-7,3,5,1,9,-7,3,5,1 %N A135449 Period 5: repeat [1, 9, -7, 3, 5]. %H A135449 <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,0,1). %F A135449 a(n) == 9a(n-1) mod 11. %F A135449 O.g.f.: -(1+9*x-7*x^2+3*x^3+5*x^4)/((x-1)*(1+x+x^2+x^3+x^4)). - _R. J. Mathar_, Jan 07 2008 %p A135449 A135449 := proc(n) op((n mod 5)+1,[1,9,-7,3,5]) ; end: seq(A135449(n),n=0..150) ; # _R. J. Mathar_, Feb 07 2009 %o A135449 (PARI) a(n)=[1,9,-7,3,5][n%5+1] \\ _Charles R Greathouse IV_, Jun 02 2011 %K A135449 sign,easy,less %O A135449 0,2 %A A135449 _Paul Curtz_, Dec 14 2007 %E A135449 More periods from _R. J. Mathar_, Feb 07 2009