A353670 a(n) = 1 if the odd part of n is a prime, otherwise 0.

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

Offset

1

Links

Antti Karttunen, Table of n, a(n) for n = 1..65537

Index entries for characteristic functions

Formula

a(n) = A010051(A000265(n)).

For n <> 2, a(n) = A010051(n) + A353671(n).

For all n >= 1, a(n) <= A353627(n), a(n) <= A329697(n) and a(n) <= A331410(n).

a(n) = [2 == A001227(n)], where [ ] is the Iverson bracket.

Prog

(PARI) A353670(n) = isprime(n>>valuation(n, 2));

Crossrefs

Characteristic function of A038550.

Cf. A000265, A001227, A010051, A329697, A331410, A353627, A353671.

Sequence in context: A324903 A011656 A295309 * A252744 A340373 A043545

Adjacent sequences: A353667 A353668 A353669 * A353671 A353672 A353673

Keyword

nonn

Author

Antti Karttunen, May 03 2022

Status

approved