A373472 a(n) = 1 if A001414(n) and A059975(n) are both multiples of 3, otherwise 0, where A001414 and A059975 are fully additive with a(p) = p and a(p) = p-1, respectively.

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

Offset

1

Links

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

Index entries for characteristic functions

Formula

a(n) = [A373369(n) == 0 (mod 3)], where [ ] is the Iverson bracket.

Prog

(PARI)
A001414(n) = ((n=factor(n))[, 1]~*n[, 2]);
A059975(n) = { my(f = factor(n)); sum(i = 1, #f~, f[i, 2]*(f[i, 1] - 1)); };
A373472(n) = (!(A001414(n)%3) && !(A059975(n)%3));

Crossrefs

Characteristic function of A373473.

Cf. A001414, A059975, A373369.

Sequence in context: A373491 A373588 A373596 * A373493 A014646 A015283

Adjacent sequences: A373469 A373470 A373471 * A373473 A373474 A373475

Keyword

nonn

Author

Antti Karttunen, Jun 06 2024

Status

approved