A331308 a(n) = min(d(n), d(A225546(n))), where d gives the number of divisors of n, A000005.

1, 2, 2, 2, 2, 4, 2, 4, 3, 4, 2, 6, 2, 4, 4, 2, 2, 6, 2, 6, 4, 4, 2, 8, 3, 4, 4, 6, 2, 8, 2, 4, 4, 4, 4, 4, 2, 4, 4, 8, 2, 8, 2, 6, 6, 4, 2, 6, 3, 6, 4, 6, 2, 8, 4, 8, 4, 4, 2, 12, 2, 4, 6, 4, 4, 8, 2, 6, 4, 8, 2, 8, 2, 4, 6, 6, 4, 8, 2, 10, 3, 4, 2, 12, 4, 4, 4, 8, 2, 12, 4, 6, 4, 4, 4, 8, 2, 6, 6, 6, 2, 8, 2, 8, 8

Offset: 1

Author

Antti Karttunen, Jan 21 2020

Keywords

• nonn

Comments

This is not equal to A000005(A331288(n)). The first difference is at n=100, where a(100) = 6, while A000005(A331288(100)) = 9. Note that A225546(100) = 243 and d(243) = 6 < d(100) = 9.

Links

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

Crossrefs

Cf. A000005, A225546, A331288, A331309, A331592.

Formula

a(n) = min(A000005(n), A331309(n)).