A175234 - OEIS

%I #11 Sep 08 2022 08:45:51

%S 2,3,5,11,23,61

%N Primes p such that 2^p+15 is also prime.

%C No additional terms through n=5000. - _Harvey P. Dale_, Apr 13 2014

%C a(7) > 5*10^5. - _Robert Price_, Sep 18 2015

%F A000040 INTERSECT A057197. [_R. J. Mathar_, May 02 2010]

%e For p=2, 2^2+15=19; p=3, 2^3+15=23; p=5, 2^5+15=47.

%t Select[Prime[Range[1000]],PrimeQ[2^#+15]&] (* _Harvey P. Dale_, Apr 13 2014 *)

%o (Magma) [p: p in PrimesUpTo(6000) | IsPrime(2^p+15) ]

%K nonn

%O 1,1

%A _Vincenzo Librandi_, Mar 09 2010