A337847 Odd integers k such that 3^((k-1)/2) == 1 (mod k*(k-2)).

457, 1297, 6481, 14401, 26497, 44101, 47521, 47881, 165601, 225457, 446881, 560737, 576721, 677041, 1037857, 1049941, 1649341, 1903981, 1934137, 2291041, 3990601, 4110121, 4262161, 4663297, 4736341, 5293081, 5317057, 5372929, 6410497, 6535681, 6651361, 8122501

Offset: 1

Author

Benoit Cloitre, Sep 26 2020

Keywords

• nonn

Comments

Computed terms are prime. Is this a possible primality test or are there pseudo primes? Terms are of the form 12k+1.

Crossrefs

Cf. A081762, A337818.

Programs

Mathematica

Select[Range[3, 10^6, 2], PowerMod[3, (# - 1)/2, #*(# - 2)] == 1 &] (* Amiram Eldar, Sep 26 2020 *)

PARI

is(n) = n%2 && n>=3 && Mod(3, n*(n-2))^((n-1)/2) == 1

Extensions

More terms from Amiram Eldar, Sep 26 2020