A353558 a(n) = 1 if n is an odd number with an odd number of prime factors (counted with multiplicity), otherwise 0.

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

Offset

1

Links

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

Index entries for characteristic functions

Formula

a(n) = A000035(n) * A066829(n).

a(n) = A000035(n) - A353557(n).

a(n) = A066829(n) - A353556(n).

Mathematica

A353558[n_] := Boole[OddQ[n] && OddQ[PrimeOmega[n]]];
Array[A353558, 100] (* Paolo Xausa, Jan 21 2026 *)
Table[If[AllTrue[{n, PrimeOmega[n]}, OddQ], 1, 0], {n, 150}] (* Harvey P. Dale, Jan 26 2026 *)

Prog

(PARI) A353558(n) = ((n%2)&&(bigomega(n)%2));

Crossrefs

Characteristic function of A067019.

Cf. A000035, A066829, A353555, A353556, A353557.

Sequence in context: A337802 A257531 A151763 * A353638 A324908 A353760

Adjacent sequences: A353555 A353556 A353557 * A353559 A353560 A353561

Keyword

nonn

Author

Antti Karttunen, May 01 2022

Status

approved