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A373474
a(n) = 1 if A001414(n) and A083345(n) are both multiples of 3, otherwise 0, where A001414 is fully additive with a(p) = p, and A083345 is the numerator of the fully additive function with a(p) = 1/p.
7
1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1
OFFSET
1
COMMENTS
Differs from A369658 for the first time at n=19683, 157464, 275562, 393660, ..., see A373476.
FORMULA
a(n) = [A373363(n) == 0 (mod 3)], where [ ] is the Iverson bracket.
a(3^9 * n) = a(n).
PROG
(PARI)
A001414(n) = ((n=factor(n))[, 1]~*n[, 2]); \\ From A001414.
A083345(n) = { my(f=factor(n)); numerator(vecsum(vector(#f~, i, f[i, 2]/f[i, 1]))); };
A373474(n) = (!(A001414(n)%3) && !(A083345(n)%3));
CROSSREFS
Characteristic function of A373475.
Cf. A001414, A083345, A373363, A373476 [k where a(k) != A369658(k)].
Sequence in context: A014548 A015087 A082784 * A369643 A105165 A058342
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jun 06 2024
STATUS
approved