A070357 a(n) = 3^n mod 28.

1, 3, 9, 27, 25, 19, 1, 3, 9, 27, 25, 19, 1, 3, 9, 27, 25, 19, 1, 3, 9, 27, 25, 19, 1, 3, 9, 27, 25, 19, 1, 3, 9, 27, 25, 19, 1, 3, 9, 27, 25, 19, 1, 3, 9, 27, 25, 19, 1, 3, 9, 27, 25, 19, 1, 3, 9, 27, 25, 19, 1, 3, 9, 27, 25, 19, 1, 3, 9, 27, 25, 19, 1, 3, 9, 27, 25, 19, 1, 3, 9, 27, 25

Offset

0,2

Links

G. C. Greubel, Table of n, a(n) for n = 0..1000

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

Formula

From R. J. Mathar, Apr 20 2010: (Start)

a(n) = a(n-1) - a(n-3) + a(n-4).

G.f.: ( -1-2*x-6*x^2-19*x^3 ) / ( (x-1)*(1+x)*(x^2-x+1) ). (End)

From G. C. Greubel, Mar 09 2016: (Start)

a(n) = a(n-6).

E.g.f.: (1/3)*( 35*cosh(x) + 49*sinh(x) - 32*exp(x/2)*cos(sqrt(3)*x/2) - 16*sqrt(3)*exp(x/2)*sin(sqrt(3)*x/2) ). (End)

Mathematica

PowerMod[3, Range[0, 90], 28] (* Harvey P. Dale, Jul 23 2012 *)

Prog

(Sage) [power_mod(3, n, 28)for n in range(0, 83)] # Zerinvary Lajos, Nov 25 2009
(PARI) a(n)=lift(Mod(3, 28)^n) \\ Charles R Greathouse IV, Mar 22 2016

Crossrefs

Cf. A000244.

Sequence in context: A036123 A168427 A070344 * A131137 A370871 A061948

Adjacent sequences: A070354 A070355 A070356 * A070358 A070359 A070360

Keyword

nonn,easy

Author

N. J. A. Sloane, May 12 2002

Status

approved