login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo

Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A152822 Periodic sequence [1,1,0,1] of length 4. 3
1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..104.

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

FORMULA

a(n) = 3/4 - (1/4)*(-1)^n + (1/2)*cos(n*Pi/2);

a(n+4) = a(n) with a(0) = a(1) = a(3) = 1 and a(2) = 0;

O.g.f.: (1+z+z^3/(1-z^4);

From Paolo P. Lava, Dec 15 2008: (Start)

a(n) = (1/8)*((n mod 4) - ((n+1) mod 4) + 3*((n+2) mod 4)((n+3) mod 4)), with n >= 0.

a(n) = (1/4)*(3 + i^n + (-i)^n - (-1)^n), with n >= 0 and i = sqrt(-1). (End)

a(n) = ceiling(cos(Pi*n/4)^2). - Wesley Ivan Hurt, Jun 12 2013

PROG

(PARI) a(n)=n%4!=2 \\ Jaume Oliver Lafont, Mar 24 2009

CROSSREFS

Cf. A026052, A026064.

Sequence in context: A085369 A188082 A046980 * A118831 A118828 A105234

Adjacent sequences:  A152819 A152820 A152821 * A152823 A152824 A152825

KEYWORD

easy,nonn,mult

AUTHOR

Richard Choulet, Dec 13 2008

EXTENSIONS

More terms from Philippe Deléham, Dec 21 2008

Keyword:mult added by Andrew Howroyd, Jul 27 2018

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 January 23 19:36 EST 2020. Contains 331175 sequences. (Running on oeis4.)