Cyclic numbers: n such that n and phi(n) are relatively prime; also n such that there is just one group of order n, i.e. A000001(n) = 1.
1, 2, 3, 5, 7, 11, 13, 15, 17, 19, 23, 29, 31, 33, 35, 37, 41, 43, 47, 51, 53, 59, 61, 65
1 seqfan posts
Sat Feb 28 00:15:38 CET 2009 [seqfan] Re: An equivalence for integer sequences (with more questions than answers)