A070376 - OEIS

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

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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)