A354031 a(n) = 1 if n > 1 and n is a power of a Pythagorean prime (prime of the form 4m+1), otherwise 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, 1, 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, 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, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 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

Offset

1

Links

Antti Karttunen, Table of n, a(n) for n = 1..65539

Index entries for characteristic functions

Formula

a(n) = [A024362(n) == 1], where [ ] is the Iverson bracket.

a(n) = A174275(n) - A354033(n).

a(n) <= A354030(n).

Prog

(PARI) A354031(n) = { my(p=0); (isprimepower(n, &p) && (1==(p%4))); };

Crossrefs

Characteristic function of A120960, Pythagorean prime powers.

Cf. A002144, A024362, A174275, A354030, A354033.

Sequence in context: A079260 A358678 A359150 * A354035 A025457 A350289

Adjacent sequences: A354028 A354029 A354030 * A354032 A354033 A354034

Keyword

nonn

Author

Antti Karttunen, May 15 2022

Status

approved