login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A010675 Period 2: repeat (0,4). 1
0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0, 4, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

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

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

FORMULA

a(n) = 2*(1-(-1)^n); a(n) = 4*(n mod 2) - Paolo P. Lava, Oct 20 2006

O.g.f.: -2/(1+x)-2/(x-1). - R. J. Mathar, Feb 19 2008

a(n) = 4*(1+floor((n+1)/2)-ceiling((n+1)/2)). - Wesley Ivan Hurt, May 21 2013

a(n) = 4*cos( Pi*(n+1)/2 )^2. - Wesley Ivan Hurt, May 21 2013

PROG

(MAGMA) &cat [[0, 4]^^50]; // Bruno Berselli, Dec 10 2015

(PARI) a(n)=n%2*4 \\ Charles R Greathouse IV, Jul 23 2016

CROSSREFS

Sequence in context: A230031 A019920 A246130 * A035673 A035638 A292142

Adjacent sequences:  A010672 A010673 A010674 * A010676 A010677 A010678

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane.

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified July 17 14:39 EDT 2019. Contains 325106 sequences. (Running on oeis4.)