A168399 a(n) = 3^n mod 13.

1, 3, 9, 1, 3, 9, 1, 3, 9, 1, 3, 9, 1, 3, 9, 1, 3, 9, 1, 3, 9, 1, 3, 9, 1, 3, 9, 1, 3, 9, 1, 3, 9, 1, 3, 9, 1, 3, 9, 1, 3, 9, 1, 3, 9, 1, 3, 9, 1, 3, 9, 1, 3, 9, 1, 3, 9, 1, 3, 9, 1, 3, 9, 1, 3, 9, 1, 3, 9, 1, 3, 9, 1, 3, 9, 1, 3, 9, 1, 3, 9, 1, 3, 9, 1, 3, 9, 1, 3, 9, 1, 3, 9

Offset: 0

Author

Zerinvary Lajos, Nov 25 2009

Keywords

• nonn
• easy

Comments

Equivalently: 3^(n+3*m) mod 13. - G. C. Greubel, Jul 20 2016

Links

• Index entries for linear recurrences with constant coefficients, signature (0,0,1).

Programs

Magma

[Modexp(3, n, 13): n in [0..110]]; // Vincenzo Librandi, Jul 21 2016

Mathematica

Table[Mod[3^n,13], {n,0,50}] (* G. C. Greubel, Jul 20 2016 *)

PARI

a(n)=lift(Mod(3,13)^n) \\ Charles R Greathouse IV, Mar 22 2016

Sage

[power_mod(3, n, 13)for n in range(0, 93)] #

Formula

From R. J. Mathar, Apr 13 2010: (Start)

a(n) = a(n-3).

G.f.: (1 + 3*x + 9*x^2)/ ((1-x)*(1+x+x^2)). (End)