A070361 - OEIS

%I #33 Dec 25 2023 11:24:11

%S 1,3,9,27,40,38,32,14,1,3,9,27,40,38,32,14,1,3,9,27,40,38,32,14,1,3,9,

%T 27,40,38,32,14,1,3,9,27,40,38,32,14,1,3,9,27,40,38,32,14,1,3,9,27,40,

%U 38,32,14,1,3,9,27,40,38,32,14,1,3,9,27,40,38,32,14,1,3,9,27,40,38,32

%N a(n) = 3^n mod 41.

%H G. C. Greubel, <a href="/A070361/b070361.txt">Table of n, a(n) for n = 0..1000</a>

%H <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,0,-1,1).

%F G.f.: (1+2*x+6*x^2+18*x^3+14*x^4)/ ((1-x) * (1+x^4)). - _R. J. Mathar_, Mar 13 2010

%F a(n) = a(n-2)+a(n-6)-a(n-4). - _Vincenzo Librandi_, Feb 06 2011

%F a(n) = a(n-8). - _G. C. Greubel_, Mar 09 2016

%t PowerMod[3, Range[0,50], 41] (* or *) Table[Mod[3^n, 41], {n, 0, 100}] (* _G. C. Greubel_, Mar 09 2016 *)

%t LinearRecurrence[{1,0,0,-1,1},{1,3,9,27,40},100] (* _Harvey P. Dale_, Mar 27 2020 *)

%o (PARI) a(n)=lift(Mod(3,41)^n) \\ _Charles R Greathouse IV_, Mar 22 2016

%Y Cf. A000244.

%K nonn,easy

%O 0,2

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