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

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• easy

Comments

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

Links

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

Programs

Mathematica

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

PARI

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

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