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A070343
a(n) = 3^n mod 25.
1
1, 3, 9, 2, 6, 18, 4, 12, 11, 8, 24, 22, 16, 23, 19, 7, 21, 13, 14, 17, 1, 3, 9, 2, 6, 18, 4, 12, 11, 8, 24, 22, 16, 23, 19, 7, 21, 13, 14, 17, 1, 3, 9, 2, 6, 18, 4, 12, 11, 8, 24, 22, 16, 23, 19, 7, 21, 13, 14, 17, 1, 3, 9, 2, 6, 18, 4, 12, 11, 8, 24, 22, 16
OFFSET
0,2
LINKS
Index entries for linear recurrences with constant coefficients, signature (1, 0, 0, 0, 0, 0, 0, 0, 0, -1, 1).
FORMULA
From R. J. Mathar, Apr 13 2010: (Start)
a(n) = a(n-1) - a(n-10) + a(n-11).
G.f.: (1+2*x+6*x^2-7*x^3+4*x^4+12*x^5-14*x^6+8*x^7-x^8-3*x^9+17*x^10)/ ((1-x) * (x ^2+1) * (x^8-x^6+x^4-x^2+1)). (End)
a(n) = a(n-20). - G. C. Greubel, Mar 12 2016
MATHEMATICA
PowerMod[3, Range[0, 50], 25] (* G. C. Greubel, Mar 12 2016 *)
PROG
(Sage) [power_mod(3, n, 25)for n in range(0, 73)] # Zerinvary Lajos, Nov 25 2009
(PARI) a(n)=lift(Mod(3, 25)^n) \\ Charles R Greathouse IV, Mar 22 2016
CROSSREFS
Sequence in context: A091473 A019675 A050129 * A050104 A175993 A021722
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, May 12 2002
STATUS
approved