A010698 Period 2: repeat (2,8).

2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2

Offset

0,1

Comments

This is the regular (simple) continued fraction for (2+sqrt(5))/2 = A176055. - Antonia Redondo Buitrago, Jul 30 2009

Links

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

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

Formula

a(n) = -3*(-1)^n+5. - Paolo P. Lava, Oct 20 2006

G.f.: 2(1+4x)/((1-x)(1+x)). a(n) = 2*A010685(n). - R. J. Mathar, Oct 20 2008

a(n) = (A010674(n)+1)*2. - Martin Ettl, Nov 09 2012

Maple

A010698:=n->5-3*(-1)^n; seq(A010698(n), n=0..100); # Wesley Ivan Hurt, Mar 26 2014

Mathematica

Table[5-3(-1)^n, {n, 0, 100}] (* Wesley Ivan Hurt, Mar 26 2014 *)
PadRight[{}, 120, {2, 8}] (* Harvey P. Dale, Oct 31 2016 *)

Prog

(Maxima) A010698(n):=if evenp(n) then 2 else 8$
makelist(A010698(n), n, 0, 30); /* Martin Ettl, Nov 09 2012 */
(PARI) a(n)=n%2*6+2 \\ Charles R Greathouse IV, Jun 11 2015

Crossrefs

Sequence in context: A229939 A237889 A064912 * A286309 A010466 A086396

Adjacent sequences: A010695 A010696 A010697 * A010699 A010700 A010701

Keyword

nonn,easy

Author

N. J. A. Sloane

Status

approved