Primes p for which the polynomial (x^79 - 1)/(x - 1) mod p is irreducible.
3, 7, 29, 37, 43, 47, 53, 59, 79, 107, 109, 113, 127, 139, 149, 193, 197, 211, 233, 271, 307, 311, 353, 359, 379, 401, 443, 449, 461, 463, 503, 509, 521, 587, 601, 607, 613, 619, 661, 691, 709, 739, 797, 827, 829, 853, 929, 937, 977, 983, 991, 1033, 1061, 1087
1
This is the 78th-degree cyclotomic polynomial. These primes p satisfy the congruence p mod 79 == {0, 3, 6, 7, 28, 29, 30, 34, 35, 37, 39, 43, 47, 48, 53, 54, 59, 60, 63, 66, 68, 70, 74, 75, 77}. The fraction of all primes in this sequence is 4/13. If we plotted n versus primepi(s(n)), then the plotted points would be very close to the line having slope 13/4.
T. D. Noe, Plot of 1000 terms
T. D. Noe, Table of 1000 terms
Wikipedia, Cyclotomic polynomial
(Mma) t = {}; n = 79; p = 1; While[Length[t] < 100, p = NextPrime[p]; If[Length[FactorList[(x^n - 1)/(x - 1), Modulus -> p]] == 2, AppendTo[t, p]]]; t
Cf. A045309, A042993, A045401, S000762-S000782.
nonn
T. D. Noe, Dec 01 2015