%I #29 Sep 08 2022 08:45:05
%S 1,7,13,19,25,31,1,7,13,19,25,31,1,7,13,19,25,31,1,7,13,19,25,31,1,7,
%T 13,19,25,31,1,7,13,19,25,31,1,7,13,19,25,31,1,7,13,19,25,31,1,7,13,
%U 19,25,31,1,7,13,19,25,31,1,7,13,19,25,31,1,7,13,19,25,31,1,7,13,19,25,31
%N a(n) = 7^n mod 36.
%H G. C. Greubel, <a href="/A070419/b070419.txt">Table of n, a(n) for n = 0..1000</a>
%H <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (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-6).
%F G.f.: ( -1-7*x-13*x^2-19*x^3-25*x^4-31*x^5 ) / ( (x-1)*(1+x)*(1+x+x^2)*(x^2-x+1) ). (End)
%t PowerMod[7, Range[0, 50], 36] (* _G. C. Greubel_, Mar 20 2016 *)
%o (Sage) [power_mod(7,n,36) for n in range(0,78)] # _Zerinvary Lajos_, Nov 27 2009
%o (PARI) a(n) = lift(Mod(7, 36)^n); \\ _Altug Alkan_, Mar 20 2016
%o (Magma) [Modexp(7, n, 36): n in [0..100]]; // _Bruno Berselli_, Mar 22 2016
%K nonn,easy
%O 0,2
%A _N. J. A. Sloane_, May 12 2002