A277048 Primes p such that the multiplicative order of 3 modulo p is prime.

11, 13, 23, 47, 59, 83, 107, 167, 179, 227, 263, 347, 359, 383, 431, 467, 479, 503, 563, 587, 683, 719, 839, 863, 887, 983, 1019, 1091, 1093, 1187, 1223, 1283, 1307, 1319, 1367, 1439, 1487, 1511, 1523, 1583, 1597, 1619, 1669, 1823, 1871, 1907, 2027

Offset: 1

Author

Vincenzo Librandi, Oct 28 2016

Keywords

• nonn

Comments

Odd primes that divide 3^p-1 for some prime p. - Robert Israel, Nov 14 2016

Links

• Robert Israel, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000040, A122094.

Programs

Magma

[p: p in PrimesInInterval(2, 4000) | IsPrime(Modorder(3, p))];

Maple

select(p -> isprime(p) and isprime(numtheory:-order(3, p)), [seq(p, p=5..10000, 2)]); # Robert Israel, Nov 14 2016

Mathematica

Select[Prime@ Range@ 310, PrimeQ@ MultiplicativeOrder[3, #] &] (* Michael De Vlieger, Oct 28 2016 *)

PARI

isok(n) = isprime(n) && isprime(znorder(Mod(3,n))); \\ Michel Marcus, Oct 28 2016