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%I #49 Dec 14 2023 05:06:19
%S 1,5,6,11,17,9,7,16,4,1,5,6,11,17,9,7,16,4,1,5,6,11,17,9,7,16,4,1,5,6,
%T 11,17,9,7,16,4,1,5,6,11,17,9,7,16,4,1,5,6,11,17,9,7,16,4,1,5,6,11,17,
%U 9,7,16,4,1,5,6,11,17,9,7,16,4,1,5,6,11,17,9,7,16,4,1,5,6,11,17,9,7,16
%N a(n) = 5^n mod 19.
%C Period 9: repeat [1, 5, 6, 11, 17, 9, 7, 16, 4].
%H G. C. Greubel, <a href="/A070373/b070373.txt">Table of n, a(n) for n = 0..999</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). [_R. J. Mathar_, Apr 20 2010]
%F From _R. J. Mathar_, Apr 20 2010: (Start)
%F a(n) = a(n-9).
%F G.f.: ( -1-5*x-6*x^2-11*x^3-17*x^4-9*x^5-7*x^6-16*x^7-4*x^8 ) / ( (x-1)*(1+x+x^2)*(x^6+x^3+1) ). (End)
%t PowerMod[5,Range[0,100],19] (* _Harvey P. Dale_, Aug 18 2015 *)
%t PadRight[{},100,{1,5,6,11,17,9,7,16,4}] (* _Harvey P. Dale_, Aug 18 2015 *)
%o (Sage) [power_mod(5,n,19) for n in range(0,89)] # _Zerinvary Lajos_, Nov 26 2009
%o (PARI) a(n) = lift(Mod(5, 19)^n); \\ _Michel Marcus_, Mar 05 2016
%o (Magma) [Modexp(5, n, 19): n in [0..100]]; // _Vincenzo Librandi_, Jun 29 2016
%Y Cf. A000351.
%K nonn
%O 0,2
%A _N. J. A. Sloane_, May 12 2002
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