A175173 Primes p such that 2^p + 5 is also prime.

3, 5, 11, 47, 53, 191, 34763

Offset: 1

Author

Vincenzo Librandi, Mar 09 2010

Keywords

• nonn

Comments

a(8) > 5*10^5. - Robert Price, Sep 18 2015

Examples

			For p=3, 2^3+5=13; p=5, 2^5+5=37; p=11, 2^11+5=2053
		

Programs

Magma

[p: p in PrimesUpTo(7000) | IsPrime(2^p+5)];

Mathematica

Select[Prime@ Range@ 1000, PrimeQ[2^# + 5] &] (* Michael De Vlieger, Sep 18 2015 *)

Formula

A000040 INTERSECT A059242. - R. J. Mathar, May 02 2010

Extensions

a(7) from Robert Price, Sep 18 2015