A010699 Period 2: repeat (2,9).

2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2

Offset

0,1

Comments

Continued fraction of 1 + sqrt(11)/3 = A176056. - R. J. Mathar, Nov 21 2011

Links

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

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

Formula

a(n) = -7/2*(-1)^n+11/2. - Paolo P. Lava, Oct 20 2006

G.f.: (2+9x)/((1-x)(1+x)). - R. J. Mathar, Nov 21 2011

a(n) = 2 + 7*(n mod 2) = 2 + 7*A000035(n). - M. F. Hasler, Feb 26 2020

Mathematica

PadRight[{}, 100, {2, 9}] (* Harvey P. Dale, Mar 25 2015 *)

Prog

(PARI) a(n)=n%2*7+2 \\ Charles R Greathouse IV, Jul 13 2016

Crossrefs

Equals 2 + A010678 = 2 + 7*A000035.

Sequence in context: A199726 A171546 A268682 * A198670 A074916 A228375

Adjacent sequences: A010696 A010697 A010698 * A010700 A010701 A010702

Keyword

nonn,easy

Author

N. J. A. Sloane

Status

approved