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

Author

N. J. A. Sloane

Keywords

• nonn
• easy

Comments

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

Links

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

Programs

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 *)

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

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