A230918 Numbers n such that phi(n)^phi(n) == gcd(n, phi(n)) (mod n), where phi is the Euler totient function.

1, 2, 3, 5, 7, 11, 12, 13, 15, 17, 19, 23, 29, 31, 33, 35, 37, 41, 43, 47, 48, 51, 53, 56, 59, 61, 65, 67, 69, 71, 73, 77, 79, 80, 83, 85, 87, 89, 91, 95, 97, 101, 103, 107, 109, 113, 115, 119, 123, 127, 131, 133, 137, 139, 141, 143, 145, 149, 151, 157, 159

Offset

1,2

Comments

It contains the sequence A003277 (cyclic numbers).

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Mathematica

Select[Range[300], PowerMod[EulerPhi[#], EulerPhi[#], #] == GCD[#,
EulerPhi[#]] &]

Prog

(PARI) is(n)=my(p=eulerphi(n), g=gcd(p, n)); Mod(p, n)^p==g \\ Charles R Greathouse IV, Dec 27 2013

Crossrefs

Cf. A003277, A230919.

Sequence in context: A137923 A163753 A131930 * A001742 A307714 A369254

Adjacent sequences: A230915 A230916 A230917 * A230919 A230920 A230921

Keyword

nonn

Author

José María Grau Ribas, Nov 01 2013

Status

approved