A070376 a(n) = 5^n mod 26.

1, 5, 25, 21, 1, 5, 25, 21, 1, 5, 25, 21, 1, 5, 25, 21, 1, 5, 25, 21, 1, 5, 25, 21, 1, 5, 25, 21, 1, 5, 25, 21, 1, 5, 25, 21, 1, 5, 25, 21, 1, 5, 25, 21, 1, 5, 25, 21, 1, 5, 25, 21, 1, 5, 25, 21, 1, 5, 25, 21, 1, 5, 25, 21, 1, 5, 25, 21, 1, 5, 25, 21, 1, 5, 25, 21, 1, 5, 25, 21, 1, 5, 25, 21

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,-1,1).

Formula

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

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

G.f.: ( -1-4*x-21*x^2 ) / ( (x-1)*(1+x^2) ). (End)

a(n) = 13 - 2*((3+2*i)*(-i)^n + (3-2*i)*i^n), where i = sqrt(-1). - Bruno Berselli, Feb 07 2011

From G. C. Greubel, Mar 13 2016: (Start)

a(n) = a(n-4).

E.g.f.: 13*exp(x) - 12*cos(x) - 8*sin(x). (End)

Maple

A070376:=n->5^n mod 26: seq(A070376(n), n=0..100); # Wesley Ivan Hurt, Mar 13 2016

Mathematica

PowerMod[5, Range[0, 50], 26] (* G. C. Greubel, Mar 13 2016 *)

Prog

(Sage) [power_mod(5, n, 26) for n in range(0, 84)] # Zerinvary Lajos, Nov 26 2009
(PARI) a(n)=lift(Mod(5, 26)^n) \\ Charles R Greathouse IV, Mar 22 2016

Crossrefs

Sequence in context: A070377 A070383 A070061 * A036139 A070382 A271379

Adjacent sequences: A070373 A070374 A070375 * A070377 A070378 A070379

Keyword

nonn,easy

Author

N. J. A. Sloane, May 12 2002

Status

approved