**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*

Index of A-numbers in seqfan: by ascending order by month by frequency by keyword

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