A009213 a(n) = gcd(d(n), phi(n)), where d is the number of divisors of n (A000005) and phi is Euler's totient function (A000010).

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

Offset

1,3

Links

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

Prog

(PARI) A009213(n) = gcd(numdiv(n), eulerphi(n)); \\ Antti Karttunen, Sep 07 2018

Crossrefs

Cf. A000005, A000010,

Cf. also A009191, A009195, A009223, A318459.

Sequence in context: A159805 A208216 A208217 * A072209 A226559 A060169

Adjacent sequences: A009210 A009211 A009212 * A009214 A009215 A009216

Keyword

nonn

Author

David W. Wilson

Status

approved