Unique-period primes in base 7, sorted.
2, 5, 19, 43, 1201, 2801, 117307, 6568801, 11898664849, 13564461457, 13841169553, 16148168401, 29078814248401, 33232924804801, 1628413557556843, 79787519018560501, 3421093417510114543, 195489390796456327201, 402488219476647465854701
1
T. D. Noe, Plot of 19 terms
Chris K. Caldwell, Unique prime
(Mma) nn = 1000; t7 = Table[c = Cyclotomic[n, 7]; c/GCD[n, c], {n, 2, nn}]; p7 = Select[t7, PrimePowerQ]; p7 = Table[FactorInteger[i][[1, 1]], {i, p7}]; Take[Sort[p7], 20]
Cf. A040017 (base-10 unique-period primes), A161509 (base 2), A064083.
Cf. S000023.
nonn,base
T. D. Noe, May 14 2014