Numbers that are unique-period primes in bases 3 and 9.
5, 41, 73, 1181, 6481, 530713, 21523361, 42521761, 47763361, 282429005041, 926510094425921, 150094634909578633, 13490012358249728401, 1716841910146256242328924544641, 1076050302914923449767311155851656076154481
1
It is not known whether this sequence is infinite. Compare S000016.
Sequence is the intersection of S000019 and S000025.
T. D. Noe, Plot of 39 terms
T. D. Noe, 39 Terms
Chris K. Caldwell, Unique prime
(Mma) nn = 500; t3 = Table[c = Cyclotomic[n, 3]; c/GCD[n, c], {n, 2, nn}]; t9 = Table[c = Cyclotomic[n, 9]; c/GCD[n, c], {n, 2, nn/2}]; Intersection[Select[t3, PrimePowerQ], Select[t9, PrimePowerQ]]
nonn,base
T. D. Noe, May 14 2014