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A070340
a(n) = 2^n mod 39.
2
1, 2, 4, 8, 16, 32, 25, 11, 22, 5, 10, 20, 1, 2, 4, 8, 16, 32, 25, 11, 22, 5, 10, 20, 1, 2, 4, 8, 16, 32, 25, 11, 22, 5, 10, 20, 1, 2, 4, 8, 16, 32, 25, 11, 22, 5, 10, 20, 1, 2, 4, 8, 16, 32, 25, 11, 22, 5, 10, 20, 1, 2, 4, 8, 16, 32, 25, 11, 22, 5, 10, 20
OFFSET
0,2
FORMULA
From R. J. Mathar, Feb 06 2011: (Start)
a(n) = a(n-1) - a(n-4) + a(n-5) - a(n-8) + a(n-9).
G.f.: ( -1-x-2*x^2-4*x^3-9*x^4-17*x^5+5*x^6+10*x^7-20*x^8 ) / ( (x-1)*(1+x+x^2)*(x^2-x+1)*(x^4-x^2+1) ). (End)
a(n) = a(n-12). - G. C. Greubel, Mar 12 2016
MATHEMATICA
PowerMod[2, Range[0, 50], 39] (* G. C. Greubel, Mar 12 2016 *)
PROG
(Sage) [power_mod(2, n, 39)for n in range(0, 72)] # Zerinvary Lajos, Nov 03 2009
(PARI) a(n)=lift(Mod(2, 39)^n) \\ Charles R Greathouse IV, Mar 22 2016
(GAP) List([0..83], n->PowerMod(2, n, 39)); # Muniru A Asiru, Jan 30 2019
CROSSREFS
Sequence in context: A070349 A070348 A130670 * A036124 A070339 A070338
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, May 12 2002
STATUS
approved