A373975 a(n) = 1 if the number of prime factors with multiplicity is a multiple of 3, otherwise 0.

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

Offset

1

Links

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

Index entries for characteristic functions

Index entries for sequences computed from exponents in factorization of n

Formula

a(n) = [A001222(n) == 0 (mod 3)], where [ ] is the Iverson bracket.

a(n) >= A101605(n).

Prog

(PARI) A373975(n) = !(bigomega(n)%3);

Crossrefs

Characteristic function of A145784.

Cf. A001222.

Cf. also A065043, A101605, A358753, A373588, A373596, A373836 for similar characteristic functions.

Sequence in context: A058342 A205808 A238897 * A374110 A297199 A373477

Adjacent sequences: A373972 A373973 A373974 * A373976 A373977 A373978

Keyword

nonn

Author

Antti Karttunen, Jun 24 2024

Status

approved