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A070414 a(n) = 7^n mod 30. 1
1, 7, 19, 13, 1, 7, 19, 13, 1, 7, 19, 13, 1, 7, 19, 13, 1, 7, 19, 13, 1, 7, 19, 13, 1, 7, 19, 13, 1, 7, 19, 13, 1, 7, 19, 13, 1, 7, 19, 13, 1, 7, 19, 13, 1, 7, 19, 13, 1, 7, 19, 13, 1, 7, 19, 13, 1, 7, 19, 13, 1, 7, 19, 13, 1, 7, 19, 13, 1, 7, 19, 13, 1, 7, 19, 13, 1, 7, 19, 13, 1, 7, 19, 13 (list; graph; refs; listen; history; text; internal format)
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). [R. J. Mathar, Apr 20 2010]

FORMULA

From Paolo P. Lava, Feb 25 2010: (Start)

a(n) = (1/6)*{28*(n mod 4)+19*[(n+1) mod 4]-8*[(n+2) mod 4]+[(n+3) mod 4]}, with n>=0.

a(n) = 10-(9/2-3/2*I)*I^n-(9/2+3/2*I)*(-I)^n, with n>=0 and I=sqrt(-1). (End)

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

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

G.f.: ( -1-6*x-13*x^2 ) / ( (x-1)*(1+x^2) ). (End)

From G. C. Greubel, Mar 20 2016: (Start)

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

E.g.f.: 10*exp(x) - 9*cos(x) - 3*sin(x). (End)

MATHEMATICA

PowerMod[7, Range[0, 50], 30] (* G. C. Greubel, Mar 20 2016 *)

PROG

(Sage) [power_mod(7, n, 30) for n in xrange(0, 84)] # Zerinvary Lajos, Nov 27 2009

(PARI) a(n) = lift(Mod(7, 30)^n); \\ Altug Alkan, Mar 20 2016

(MAGMA) [Modexp(7, n, 30): n in [0..100]]; // Bruno Berselli, Mar 22 2016

CROSSREFS

Sequence in context: A156295 A226932 A245167 * A195870 A125257 A195867

Adjacent sequences:  A070411 A070412 A070413 * A070415 A070416 A070417

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, May 12 2002

STATUS

approved

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Last modified July 21 04:27 EDT 2017. Contains 289632 sequences.