A070377 - OEIS

%I #32 Dec 07 2019 12:18:23

%S 1,5,25,17,4,20,19,14,16,26,22,2,10,23,7,8,13,11,1,5,25,17,4,20,19,14,

%T 16,26,22,2,10,23,7,8,13,11,1,5,25,17,4,20,19,14,16,26,22,2,10,23,7,8,

%U 13,11,1,5,25,17,4,20,19,14,16,26,22,2,10,23,7,8,13,11,1,5,25,17,4,20

%N a(n) = 5^n mod 27.

%H G. C. Greubel, <a href="/A070377/b070377.txt">Table of n, a(n) for n = 0..1000</a>

%H <a href="/index/Rec#order_10">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,0,0,0,0,0,0,-1,1).

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

%F a(n) = a(n-1) - a(n-9) + a(n-10).

%F G.f.: ( -1-4*x-20*x^2+8*x^3+13*x^4-16*x^5+x^6+5*x^7-2*x^8-11*x^9 ) / ( (x-1)*(1+x)*(x^2-x+1)*(x^6-x^3+1) ). (End)

%F a(n) = a(n-18). - _G. C. Greubel_, Mar 13 2016

%p A070377:=n->5^n mod 27; seq(A070377(n), n=0..100); # _Wesley Ivan Hurt_, Dec 02 2013

%t PowerMod[5,Range[0,80],27] (* or *) LinearRecurrence[ {1,0,0,0,0,0,0,0,-1,1},{1,5,25,17,4,20,19,14,16,26},80] (* _Harvey P. Dale_, Aug 12 2012 *)

%o (Sage) [power_mod(5,n,27) for n in range(0,78)] # _Zerinvary Lajos_, Nov 26 2009

%o (PARI) a(n)=lift(Mod(5,27)^n) \\ _Charles R Greathouse IV_, Mar 22 2016

%K nonn,easy

%O 0,2

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