A374126 a(n) = gcd(sigma(n), sopfr(n)), where sigma is the sum of divisors, and sopfr is the sum of prime factors with repetition.

1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 7, 1, 3, 8, 1, 1, 1, 1, 3, 2, 1, 1, 3, 1, 3, 1, 1, 1, 2, 1, 1, 2, 1, 12, 1, 1, 3, 8, 1, 1, 12, 1, 3, 1, 1, 1, 1, 1, 3, 4, 1, 1, 1, 8, 1, 2, 1, 1, 12, 1, 3, 13, 1, 6, 16, 1, 21, 2, 2, 1, 3, 1, 3, 1, 1, 6, 6, 1, 1, 1, 1, 1, 14, 2, 3, 8, 1, 1, 13, 4, 3, 2, 1, 24, 1, 1, 1, 1, 7, 1, 2

Offset: 1

Author

Antti Karttunen, Jul 06 2024

Keywords

• nonn

Links

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

Crossrefs

Cf. A000203, A001414, A086665.

Programs

PARI

A001414(n) = ((n=factor(n))[, 1]~*n[, 2]);
A374126(n) = gcd(A001414(n), sigma(n));

Formula

a(n) = gcd(A000203(n), A001414(n)).

a(n) = gcd(A000203(n), A086665(n)) = gcd(A001414(n), A086665(n)).