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A131712 Period 4: repeat [1, 3, 7, 9]. 2
1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Terms of the simple continued fraction of 58/(17*sqrt(285)-243). - Paolo P. Lava, Aug 05 2009

Decimal expansion of 1379/9999. - Klaus Brockhaus, May 21 2010

LINKS

Table of n, a(n) for n=0..104.

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

FORMULA

a(n) = (1/6)*(17*(n mod 6) + 2*((n+1) mod 4) - 2*((n+2) mod 4) - ((n+3) mod 4)). - Paolo P. Lava, Oct 02 2007

G.f.: (1+3*x+7*x^2+9*x^3)/((1-x)*(x+1)*(1+x^2)). - R. J. Mathar, Nov 14 2007

a(n) = 5-(3/2-(3/2)*i)*i^n-(-1)^n-(3/2+(3/2)*i)*(-i)^n, where i = sqrt(-1). - Paolo P. Lava, Jul 17 2008

From Wesley Ivan Hurt, Jul 09 2016: (Start)

a(n) = a(n-4) for n>3.

a(n) = 5 - 3*cos(n*Pi/2) - cos(n*Pi) - 3*sin(n*Pi/2) - I*sin(n*Pi). (End)

MAPLE

seq(op([1, 3, 7, 9]), n=0..40); # Wesley Ivan Hurt, Jul 09 2016

MATHEMATICA

PadRight[{}, 100, {1, 3, 7, 9}] (* Wesley Ivan Hurt, Jul 09 2016 *)

PROG

(PARI) a(n)=1+2*(n%4)+2*(n%4\2) \\ Jaume Oliver Lafont, Aug 28 2009

(MAGMA) &cat[[1, 3, 7, 9]: k in [1..30]] // Vincenzo Librandi, Nov 23 2010

CROSSREFS

Cf. A072845, A131707.

Cf. A178148 (decimal expansion of (243+17*sqrt(285))/402). - Klaus Brockhaus, May 21 2010

Sequence in context: A244338 A336045 A090458 * A072845 A197481 A197682

Adjacent sequences:  A131709 A131710 A131711 * A131713 A131714 A131715

KEYWORD

nonn,easy

AUTHOR

Paul Curtz, Sep 14 2007

EXTENSIONS

More terms from Klaus Brockhaus, May 21 2010

STATUS

approved

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Last modified July 12 21:31 EDT 2020. Contains 335669 sequences. (Running on oeis4.)