A322301 - OEIS

%I #10 Sep 08 2022 08:46:23

%S 3,7,13,127,3313,23473,819739

%N Primes p such that 5*2^p + 1 is also prime.

%C Primes in A002254.

%p select(p->isprime(p) and isprime(5*2^p+1),[$0..5000]); # _Muniru A Asiru_, Dec 19 2018

%t Select[Prime[Range[4000]], PrimeQ[5 2^# + 1] &]

%o (Magma) [p: p in PrimesUpTo (10000) | IsPrime(5*2^p+1)];

%Y Cf. A002254, A175172.

%K nonn,more

%O 1,1

%A _Vincenzo Librandi_, Dec 19 2018