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

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

Offset

1,1

Comments

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

Links

Table of n, a(n) for n=1..7.

Formula

A000040 INTERSECT A059242. [R. J. Mathar, May 02 2010]

Example

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

Mathematica

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

Prog

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

Crossrefs

Sequence in context: A144467 A049883 A059242 * A268510 A004203 A201473

Adjacent sequences: A175170 A175171 A175172 * A175174 A175175 A175176

Keyword

nonn

Author

Vincenzo Librandi, Mar 09 2010

Extensions

a(7) from Robert Price, Sep 18 2015

Status

approved