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A010686 Periodic sequence: Repeat 1,5. 16
1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1 (list; graph; refs; listen; history; internal format)
OFFSET

0,2

COMMENTS

5^n mod 12. [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Nov 25 2009]

Also continued fraction expansion of (5+3*sqrt(5))/10. - Bruno Berselli, Sep 30 2011

LINKS

Burkard Polster, Juggling, maths and a beautiful mind [From Parthasarathy Nambi, Nov 20 2009]

Index to sequences with linear recurrences with constant coefficients, signature (0,1).

FORMULA

Contribution from Paul Barry, Jun 03 2003: (Start)

  G.f.: (1+5*x)/((1-x)*(1+x)).

  E.g.f.: 3*exp(x)-2*exp(-x).

  a(n) = 3-2(-1)^n.

  a(n) = 5^((1-(-1)^n)/2) = 5^(ceiling(n/2)-floor(n/2)). (End)

a(n) = 5*(n mod 2)+(n+1) mod 2 - Paolo P. Lava, Oct 20 2006

a(n) = 5^n mod 24. - Paul Curtz, Jan 09 2008

a(n) = A000364(n+1) mod 10. - Paul Curtz, Feb 09 2010

MAPLE

[seq (modp((4*n+1), 8), n=0..80)]; - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Dec 01 2006

PROG

(Other) sage: [power_mod(5, n, 12)for n in xrange(0, 101)] #o [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Nov 25 2009]

CROSSREFS

Sequence in context: A019840 A205109 A144432 * A021070 A176260 A098190

Adjacent sequences:  A010683 A010684 A010685 * A010687 A010688 A010689

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com).

EXTENSIONS

Definition rewritten by Bruno Berselli, Sep 30 2011

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Last modified February 15 10:28 EST 2012. Contains 205763 sequences.