A010720 - OEIS

A010720

Period 2: repeat (5,9).

5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5, 9, 5

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OFFSET

0,1

COMMENTS

Continued fraction expansion of A176324. - R. J. Mathar, Mar 08 2012

LINKS

Table of n, a(n) for n=0..80.

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

FORMULA

a(n) = -2*(-1)^n + 7. - Paolo P. Lava, Oct 20 2006

a(n) = a(n-2) for n > 1; a(0) = 5, a(1) = 9. G.f.: (5+9*x)/((1-x)*(1+x)). - Vincenzo Librandi, Aug 01 2010

MATHEMATICA

Table[5 + 4 Mod[n, 2], {n, 0, 50}] (* Jinyuan Wang, Feb 26 2020 *)

PROG

(PARI) a(n)=n%2*4+5 \\ Charles R Greathouse IV, Jul 13 2016

CROSSREFS

Sequence in context: A385521 A200283 A355178 * A094389 A057821 A133742

Adjacent sequences: A010717 A010718 A010719 * A010721 A010722 A010723

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane

STATUS

approved