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

0,2

Comments

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

Links

Table of n, a(n) for n=0..86.

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

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

Mathematica

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

Prog

(PARI) a(n)=n%2*3 \\ Charles R Greathouse IV, Nov 20 2011
(Maxima) makelist(if evenp(n) then 0 else 3, n, 0, 30); /* Martin Ettl, Nov 09 2012 */
(Magma) &cat [[0, 3]^^50]; // Bruno Berselli, Dec 29 2015
(Scala) (0 to 99).map(_ % 2 * 3) // Alonso del Arte, Mar 25 2020

Crossrefs

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

Sequence in context: A273128 A183035 A115634 * A021037 A053387 A221170

Adjacent sequences: A010671 A010672 A010673 * A010675 A010676 A010677

Keyword

nonn,cons,easy

Author

N. J. A. Sloane

Extensions

More terms from Paolo P. Lava, Oct 20 2006

Status

approved