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A168400 3^n mod 15. 1
1, 3, 9, 12, 6, 3, 9, 12, 6, 3, 9, 12, 6, 3, 9, 12, 6, 3, 9, 12, 6, 3, 9, 12, 6, 3, 9, 12, 6, 3, 9, 12, 6, 3, 9, 12, 6, 3, 9, 12, 6, 3, 9, 12, 6, 3, 9, 12, 6, 3, 9, 12, 6, 3, 9, 12, 6, 3, 9, 12, 6, 3, 9, 12, 6, 3, 9, 12, 6, 3, 9, 12, 6, 3, 9, 12, 6, 3, 9, 12, 6, 3, 9, 12, 6, 3, 9, 12, 6, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

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

FORMULA

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

a(n) = a(n-1) -a(n-2) +a(n-3), n>3.

G.f.: (1 + 2*x + 7*x^2 + 5*x^3)/((1-x)*(1+x^2)). (End)

MATHEMATICA

Table[Mod[3^n, 15], {n, 0, 50}] (* G. C. Greubel, Jul 21 2016 *)

PROG

(Sage) [power_mod(3, n, 15) for n in xrange(0, 90)]

(PARI) a(n)=lift(Mod(3, 15)^n) \\ Charles R Greathouse IV, Mar 22 2016

(MAGMA) [Modexp(3, n, 15): n in [0..110]]; // Vincenzo Librandi, Jul 21 2016

CROSSREFS

Sequence in context: A069871 A061957 A136984 * A310318 A310319 A073105

Adjacent sequences:  A168397 A168398 A168399 * A168401 A168402 A168403

KEYWORD

nonn,easy

AUTHOR

Zerinvary Lajos, Nov 25 2009

STATUS

approved

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Last modified November 17 08:39 EST 2019. Contains 329217 sequences. (Running on oeis4.)