A010674 Period 2: repeat (0,3).

0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• cons
• easy

Comments

Also decimal expansion of 1/33 = .030303030...

Links

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

Crossrefs

Cf. A010680 (1/11), A010695 (2^(1 - (-1)^n) + 1).

Programs

Magma

&cat [[0,3]^^50]; // Bruno Berselli, Dec 29 2015

Mathematica

3Mod[Range[0, 99], 2] (* Alonso del Arte, Mar 25 2020 *)

Maxima

makelist(if evenp(n) then 0 else 3, n, 0, 30); /* Martin Ettl, Nov 09 2012 */

PARI

a(n)=n%2*3 \\ Charles R Greathouse IV, Nov 20 2011

Scala

(0 to 99).map( % 2 * 3) // _Alonso del Arte, Mar 25 2020

Formula

a(n) = (3/2)*(1 - (-1)^n) = 3*(n mod 2). - Paolo P. Lava, Oct 20 2006

a(n) = A010698(n)/2 - 1. - Martin Ettl, Nov 11 2012

a(n) = 2^(1 - (-1)^n) - 1. - Bruno Berselli, Dec 29 2015

From Chai Wah Wu, Jun 04 2016: (Start)

a(n) = a(n-2) for n >= 2.

G.f.: 3*x/(1 - x^2). (End)

E.g.f.: 3*sinh(x). - Ilya Gutkovskiy, Jun 04 2016

Extensions

More terms from Paolo P. Lava, Oct 20 2006