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%I #42 Dec 14 2023 05:06:30
%S 1,7,22,19,25,13,10,16,4,1,7,22,19,25,13,10,16,4,1,7,22,19,25,13,10,
%T 16,4,1,7,22,19,25,13,10,16,4,1,7,22,19,25,13,10,16,4,1,7,22,19,25,13,
%U 10,16,4,1,7,22,19,25,13,10,16,4,1,7,22,19,25,13,10,16,4,1,7,22,19,25,13
%N a(n) = 7^n mod 27.
%C Period 9: repeat [1, 7, 22, 19, 25, 13, 10, 16, 4]. - _Wesley Ivan Hurt_, Feb 28 2014
%H G. C. Greubel, <a href="/A070412/b070412.txt">Table of n, a(n) for n = 0..1000</a>
%H <a href="/index/Rec#order_09">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,0,0,0,0,0,1).
%F From _R. J. Mathar_, Apr 20 2010: (Start)
%F a(n) = a(n-9).
%F G.f.: ( -1-7*x- 22*x^2-19*x^3-25*x^4-13*x^5-10*x^6-16*x^7-4*x^8 ) / ( (x-1)*(1+x+x^2)*(x^6+x^3+1) ). (End)
%o (Sage) [power_mod(7,n,27) for n in range(0,78)] # _Zerinvary Lajos_, Nov 27 2009
%o (PARI) a(n) = lift(Mod(7, 27)^n); \\ _Altug Alkan_, Mar 20 2016
%o (Magma) [Modexp(7, n, 27): n in [0..100]]; // _Bruno Berselli_, Mar 22 2016
%K nonn,easy
%O 0,2
%A _N. J. A. Sloane_, May 12 2002