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A230918 Numbers n such that phi(n)^phi(n) == gcd(n, phi(n)) (mod n), where phi is the Euler totient function. 2
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 (list; graph; refs; listen; history; text; internal format)
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 A073085

Adjacent sequences:  A230915 A230916 A230917 * A230919 A230920 A230921

KEYWORD

nonn

AUTHOR

José María Grau Ribas, Nov 01 2013

STATUS

approved

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Last modified October 23 17:37 EDT 2021. Contains 348215 sequences. (Running on oeis4.)