OFFSET
1,1
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
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 *)
PROG
(Magma) [p: p in PrimesInInterval(2, 4000) | IsPrime(Modorder(3, p))];
(PARI) isok(n) = isprime(n) && isprime(znorder(Mod(3, n))); \\ Michel Marcus, Oct 28 2016
CROSSREFS
KEYWORD
nonn
AUTHOR
Vincenzo Librandi, Oct 28 2016
STATUS
approved