A070446 a(n) = n^2 mod 24.

0, 1, 4, 9, 16, 1, 12, 1, 16, 9, 4, 1, 0, 1, 4, 9, 16, 1, 12, 1, 16, 9, 4, 1, 0, 1, 4, 9, 16, 1, 12, 1, 16, 9, 4, 1, 0, 1, 4, 9, 16, 1, 12, 1, 16, 9, 4, 1, 0, 1, 4, 9, 16, 1, 12, 1, 16, 9, 4, 1, 0, 1, 4, 9, 16, 1, 12, 1, 16, 9, 4, 1, 0, 1, 4, 9, 16, 1, 12, 1, 16, 9, 4, 1, 0, 1, 4, 9, 16, 1, 12, 1

Offset

0,3

Comments

Periodic with period = 12. - Harvey P. Dale, Jun 19 2014

From Jesse Fiedler, Aug 23 2019: (Start)

If a(n) = 1, then n is odd and is not divisible by 3.

For n <= 7919 and a(n)=1, approximately 37.8% of values of n are prime.

For n <= 104729, and a(n)=1, approximately 28.64% of values of n are prime.

(End)

Links

G. C. Greubel, Table of n, a(n) for n = 0..1000

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

Mathematica

Table[Mod[n^2, 24], {n, 0, 200}] (* Vladimir Joseph Stephan Orlovsky, Apr 23 2011 *)
PowerMod[Range[0, 100], 2, 24] (* or *) PadRight[{}, 100, {0, 1, 4, 9, 16, 1, 12, 1, 16, 9, 4, 1}] (* Harvey P. Dale, Jun 19 2014 *)

Prog

(PARI) a(n)=n^2%24 \\ Charles R Greathouse IV, Apr 06 2016

Crossrefs

Sequence in context: A106546 A276191 A007893 * A258682 A070445 A070444

Adjacent sequences: A070443 A070444 A070445 * A070447 A070448 A070449

Keyword

nonn,easy

Author

N. J. A. Sloane, May 12 2002

Status

approved