A167425 a(n) = 2^n mod 26.

1, 2, 4, 8, 16, 6, 12, 24, 22, 18, 10, 20, 14, 2, 4, 8, 16, 6, 12, 24, 22, 18, 10, 20, 14, 2, 4, 8, 16, 6, 12, 24, 22, 18, 10, 20, 14, 2, 4, 8, 16, 6, 12, 24, 22, 18, 10, 20, 14, 2, 4, 8, 16, 6, 12, 24, 22, 18, 10, 20, 14, 2, 4, 8, 16, 6, 12, 24, 22, 18, 10, 20, 14, 2, 4, 8, 16, 6, 12, 24

Offset

0,2

Links

Table of n, a(n) for n=0..79.

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

Formula

From R. J. Mathar, Apr 13 2010: (Start)

G.f.: (x+2*x^2+4*x^3+8*x^4-10*x^5+7*x^6+13*x^7+1)/((1-x)*(x^2+1)*(x^4-x^2+1)).

a(n) = +a(n-1) -a(n-6) +a(n-7) for n>7. (End)

Mathematica

PowerMod[2, Range[0, 100], 26] (* or *) PadRight[{1}, 100, {14, 2, 4, 8, 16, 6, 12, 24, 22, 18, 10, 20}] (* Harvey P. Dale, Aug 02 2013 *)

Prog

(Sage) [power_mod(2, n, 26)for n in range(0, 87)] #
(PARI) a(n)=lift(Mod(2, 26)^n) \\ Charles R Greathouse IV, Mar 22 2016

Crossrefs

Sequence in context: A088975 A306601 A237851 * A378107 A212638 A016018

Adjacent sequences: A167422 A167423 A167424 * A167426 A167427 A167428

Keyword

nonn,easy

Author

Zerinvary Lajos, Nov 03 2009

Status

approved