A340195 a(n) = Sum_{divisors d of n} A049559(d), where A049559(x) = gcd(phi(x), x-1).

1, 2, 3, 3, 5, 5, 7, 4, 5, 7, 11, 7, 13, 9, 9, 5, 17, 8, 19, 9, 13, 13, 23, 9, 9, 15, 7, 13, 29, 13, 31, 6, 17, 19, 13, 11, 37, 21, 17, 11, 41, 17, 43, 15, 15, 25, 47, 11, 13, 12, 21, 19, 53, 11, 17, 15, 25, 31, 59, 17, 61, 33, 17, 7, 33, 25, 67, 21, 29, 19, 71, 14, 73, 39, 15, 25, 21, 21, 79, 13, 9, 43, 83, 23, 25, 45, 33

Offset: 1

Author

Antti Karttunen, Jan 02 2021

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..16384

Crossrefs

Inverse Möbius transform of A049559.

Cf. A000010, A340196.

Cf. also A340192.

Programs

PARI

A049559(n) = gcd(eulerphi(n), n-1);
A340195(n) = sumdiv(n,d,A049559(d));

Formula

a(n) = Sum_{d|n} A049559(d).

a(n) = n - A340196(n).