Unique-period primes in base 9, sorted.
5, 41, 73, 1181, 6481, 530713, 21523361, 42521761, 47763361, 282429005041, 926510094425921, 150094634909578633, 13490012358249728401, 1716841910146256242328924544641, 1076050302914923449767311155851656076154481
1
T. D. Noe, Plot of 15 terms
Chris K. Caldwell, Unique prime
(Mma) nn = 1000; t9 = Table[c = Cyclotomic[n, 9]; c/GCD[n, c], {n, 2, nn}]; p9 = Select[t9, PrimePowerQ]; p9 = Table[FactorInteger[i][[1, 1]], {i, p9}]; Take[Sort[p9], 15]
Cf. A040017 (base-10 unique-period primes), A161509 (base 2).
Cf. S000025.
nonn,base
T. D. Noe, May 14 2014