A284660 Terms of A161897 that are not in A005385.

3083, 4931, 6563, 9923, 166667, 865643, 1306667, 2266883, 3367367, 3906563, 4128959, 5493179, 5591039, 6040187, 9122963, 9402179, 9871403, 10174343, 13081379, 13756403, 14924003, 16550243, 24165287, 29492747, 32140859, 34633427, 38425643, 42249587, 42258779, 43014659, 45067523, 52678643

Offset: 1

Author

Robert Israel, Mar 31 2017

Keywords

• nonn

Comments

Primes p such that q = (p-1)/2 is composite, 3^q == 1 (mod p) and 3^(q-1) == 1 (mod p-1).

All terms == 5 (mod 6).

Examples

			p = 3083 is in the sequence because it is prime, q = (3083-1)/2 = 23*67 is composite, 3^q == 1 (mod p) and 3^(q-1) == 1 mod (p-1).
		

Links

• Robert Israel, Table of n, a(n) for n = 1..212

Crossrefs

Cf. A005385, A161897.

Programs

Maple

filter:= p -> isprime(p) and not isprime((p-1)/2) and
   3&^((p-3)/2)  mod (p-1) = 1 and
   3 &^((p-1)/2) mod p = 1;
select(filter, [seq(p, p=5..10^7, 6)]); # Robert Israel, Mar 31 2017