A060679 Orders of non-cyclic groups.

4, 6, 8, 9, 10, 12, 14, 16, 18, 20, 21, 22, 24, 25, 26, 27, 28, 30, 32, 34, 36, 38, 39, 40, 42, 44, 45, 46, 48, 49, 50, 52, 54, 55, 56, 57, 58, 60, 62, 63, 64, 66, 68, 70, 72, 74, 75, 76, 78, 80, 81, 82, 84, 86, 88, 90, 92, 93, 94, 96, 98, 99, 100, 102, 104, 105, 106, 108

Offset

1,1

Comments

Numbers n such that x^n==1 (mod n) has solutions 2<=x<=n - Benoit Cloitre, May 10 2002

Links

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

Formula

a(n) = n + O(n/log log log n). - Charles R Greathouse IV, Apr 16 2012

Prog

(PARI) is(n)=gcd(n, eulerphi(n))>1 \\ Charles R Greathouse IV, Apr 16 2012

Crossrefs

Complement of A003277.

Sequence in context: A117097 A077135 A110615 * A051234 A327776 A102554

Adjacent sequences: A060676 A060677 A060678 * A060680 A060681 A060682

Keyword

nonn

Author

Ahmed Fares (ahmedfares(AT)my-deja.com), Apr 19 2001

Extensions

More terms from Vladeta Jovovic, Jul 05 2001

Status

approved