A331176 a(n) = n - n/gcd(n, phi(n)), where phi is Euler totient function.

0, 0, 0, 2, 0, 3, 0, 6, 6, 5, 0, 9, 0, 7, 0, 14, 0, 15, 0, 15, 14, 11, 0, 21, 20, 13, 24, 21, 0, 15, 0, 30, 0, 17, 0, 33, 0, 19, 26, 35, 0, 35, 0, 33, 30, 23, 0, 45, 42, 45, 0, 39, 0, 51, 44, 49, 38, 29, 0, 45, 0, 31, 56, 62, 0, 33, 0, 51, 0, 35, 0, 69, 0, 37, 60, 57, 0, 65, 0, 75, 78, 41, 0, 77, 0, 43, 0, 77, 0, 75

Offset: 1

Author

Antti Karttunen, Jan 11 2020

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..16384
• Antti Karttunen, Data supplement: n, a(n) computed for n = 1..65537

Crossrefs

Cf. A000010, A009195, A109395.

Cf. A003277 (indices of zeros).

Programs

Mathematica

Table[n-n/GCD[n,EulerPhi[n]],{n,90}] (* Harvey P. Dale, Aug 20 2020 *)

PARI

A331176(n) = (n - (n/gcd(n, eulerphi(n))));

Formula

a(n) = n - A109395(n).