A373979 a(n) = 1 if n is a nonprime of the form 4*k + 3, otherwise 0.

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0

Offset

1

Links

Antti Karttunen, Table of n, a(n) for n = 1..100000

Index entries for characteristic functions

Mathematica

a[n_]:=Boole[!PrimeQ[n]&&Mod[n, 4]==3]; Array[a, 125](* Stefano Spezia, Jun 25 2024 *)

Prog

(PARI) A373979(n) = (!isprime(n) && 3==(n%4));

Crossrefs

Characteristic function of A091236.

Cf. also A079261, A373978.

Sequence in context: A360111 A359162 A327932 * A359546 A354989 A277161

Adjacent sequences: A373976 A373977 A373978 * A373980 A373981 A373982

Keyword

nonn

Author

Antti Karttunen, Jun 25 2024

Status

approved