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a(n) = 6^n mod 13.
1

%I #30 Dec 07 2019 12:18:23

%S 1,6,10,8,9,2,12,7,3,5,4,11,1,6,10,8,9,2,12,7,3,5,4,11,1,6,10,8,9,2,

%T 12,7,3,5,4,11,1,6,10,8,9,2,12,7,3,5,4,11,1,6,10,8,9,2,12,7,3,5,4,11,

%U 1,6,10,8,9,2,12,7,3,5,4,11,1,6,10,8,9,2,12,7,3,5,4,11,1,6,10,8,9,2,12,7,3

%N a(n) = 6^n mod 13.

%C Period 12: repeat [1, 6, 10, 8, 9, 2, 12, 7, 3, 5, 4, 11]. - _Harvey P. Dale_, Feb 26 2014

%H G. C. Greubel, <a href="/A070393/b070393.txt">Table of n, a(n) for n = 0..1000</a>

%H <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,0,0,0,-1,1). [_R. J. Mathar_, Apr 20 2010]

%F From _R. J. Mathar_, Apr 20 2010: (Start)

%F a(n) = a(n-1) - a(n-6) + a(n-7).

%F G.f.: (-1-5*x-4*x^2+2*x^3-x^4+7*x^5-11*x^6)/((x-1)*(x^2+1)*(x^4-x^2+1)). (End)

%F a(n) = a(n-12). - _G. C. Greubel_, Mar 18 2016

%t PowerMod[6,Range[0,100],13] (* _Harvey P. Dale_, Feb 26 2014 *)

%t LinearRecurrence[{1,0,0,0,0,-1,1},{1,6,10,8,9,2,12},100] (* _Harvey P. Dale_, Feb 26 2014 *)

%o (Sage) [power_mod(6,n,13)for n in range(0,93)] # _Zerinvary Lajos_, Nov 26 2009

%o (PARI) a(n) = lift(Mod(6, 13)^n); \\ _Altug Alkan_, Mar 18 2016

%K nonn

%O 0,2

%A _N. J. A. Sloane_, May 12 2002