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A230919
Non-cyclic numbers n such that phi(n)^phi(n) == gcd(n, phi(n)) (mod n), where phi is Euler totient function.
2
12, 48, 56, 80, 192, 240, 252, 351, 448, 768, 992, 1100, 1134, 1260, 1280, 1824, 1872, 2016, 3072, 3300, 3520, 3584, 3840, 3875, 4352, 5103, 6156, 9072, 9120, 9288, 9477, 9984, 10962, 11132, 11264, 12288, 13056, 16128, 16256, 20480, 20592, 21760, 22736
OFFSET
1,1
COMMENTS
The cyclic numbers satisfy phi(n)^phi(n) == gcd(n, phi(n))== 1 (mod n).
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..3238
MATHEMATICA
Select[Range[40000], PowerMod[EulerPhi[#], EulerPhi[#], #] > 1 && PowerMod[EulerPhi[#], EulerPhi[#], #] == GCD[#, EulerPhi[#]] &]
PROG
(PARI) is(n)=my(p=eulerphi(n), g=gcd(p, n)); g>1 && Mod(p, n)^p==g \\ Charles R Greathouse IV, Dec 27 2013
CROSSREFS
Sequence in context: A002612 A124351 A335101 * A181925 A118903 A324747
KEYWORD
nonn
AUTHOR
STATUS
approved