A175171 Primes p such that 3*2^p-1 is also prime.

2, 3, 7, 11, 43, 103, 827, 7559, 26459, 164987

Offset: 1

Author

Vincenzo Librandi, Mar 09 2010

Keywords

• nonn
• more

Comments

These are the primes in A002235. [R. J. Mathar, May 02 2010]

Examples

			For p=2, 3*2^2-1=11; p=3, 3*2^3-1=23; p=7, 3*2^7-1=383
		

Crossrefs

Cf. A002235.

Programs

Magma

[p: p in PrimesUpTo(7000) | IsPrime(3*2^p-1) ];

Extensions

3 more terms from R. J. Mathar, May 02 2010