Numbers that are unique-period primes in bases 2 and 4.
5, 7, 13, 17, 41, 241, 257, 61681, 65537, 15790321, 4278255361, 4562284561, 18446744069414584321, 291280009243618888211558641, 78919881726271091143763623681, 84159375948762099254554456081, 84179842077657862011867889681
1
It is not known whether this sequence is infinite. Compare S000016.
Sequence is the intersection of A161509 and S000019.
T. D. Noe, Plot of 35 terms
T. D. Noe, 35 Terms
Chris K. Caldwell, Unique prime
(Mma) nn = 500; t2 = Table[c = Cyclotomic[n, 2]; c/GCD[n, c], {n, 2, nn}]; t4 = Table[c = Cyclotomic[n, 4]; c/GCD[n, c], {n, 2, nn/2}]; Intersection[Select[t2, PrimePowerQ], Select[t4, PrimePowerQ]]
nonn,base
T. D. Noe, May 14 2014