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A373975
a(n) = 1 if the number of prime factors with multiplicity is a multiple of 3, otherwise 0.
2
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
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
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jun 24 2024
STATUS
approved