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A168399
a(n) = 3^n mod 13.
2
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
0,2
COMMENTS
Equivalently: 3^(n+3*m) mod 13. - G. C. Greubel, Jul 20 2016
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)
MATHEMATICA
Table[Mod[3^n, 13], {n, 0, 50}] (* G. C. Greubel, Jul 20 *)
PROG
(Sage) [power_mod(3, n, 13)for n in range(0, 93)] #
(PARI) a(n)=lift(Mod(3, 13)^n) \\ Charles R Greathouse IV, Mar 22 2016
(Magma) [Modexp(3, n, 13): n in [0..110]]; // Vincenzo Librandi, Jul 21 2016
CROSSREFS
Sequence in context: A304022 A103556 A254348 * A290375 A245081 A010631
KEYWORD
nonn,easy
AUTHOR
Zerinvary Lajos, Nov 25 2009
STATUS
approved