A373368 a(n) = gcd(n, A059975(n)), where A059975 is fully additive with a(p) = p-1.

1, 1, 1, 2, 1, 3, 1, 1, 1, 5, 1, 4, 1, 7, 3, 4, 1, 1, 1, 2, 1, 11, 1, 1, 1, 13, 3, 4, 1, 1, 1, 1, 3, 17, 5, 6, 1, 19, 1, 1, 1, 3, 1, 4, 1, 23, 1, 6, 1, 1, 3, 2, 1, 1, 1, 1, 1, 29, 1, 4, 1, 31, 1, 2, 1, 1, 1, 2, 3, 1, 1, 1, 1, 37, 5, 4, 1, 3, 1, 8, 1, 41, 1, 2, 5, 43, 3, 1, 1, 9, 1, 4, 1, 47, 1, 1, 1, 1, 1, 10

Offset: 1

Author

Antti Karttunen, Jun 05 2024

Keywords

• nonn

Links

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

Crossrefs

Cf. A059975, A108269 (positions of even terms), A359794 (of odd terms), A359832 (parity of terms).

Cf. also A082299, A373361, A373369.

Programs

PARI

A059975(n) = {my(f = factor(n)); sum(i = 1, #f~, f[i, 2]*(f[i, 1] - 1)); };
A373368(n) = gcd(n, A059975(n));