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Primes of the form 5+3*2^n.
2

%I #9 Sep 08 2022 08:46:02

%S 11,17,29,53,101,197,389,773,49157,196613,1572869,12582917,50331653,

%T 402653189,1610612741,12884901893,824633720837,54043195528445957,

%U 432345564227567621,3458764513820540933,226673591177742970257413,59421121885698253195157962757

%N Primes of the form 5+3*2^n.

%H Vincenzo Librandi, <a href="/A211486/b211486.txt">Table of n, a(n) for n = 1..40</a>

%t Select[5+2^Range[0,2000]*3,PrimeQ]

%o (Magma) [ a: n in [0..250] | IsPrime(a) where a is 5+3*2^n ]

%o (PARI) {for(n=0, 80, if(isprime(k=5+3*2^n), print1(k, ", ")))}

%Y Cf. A057913 (n such that 3*2^n + 5 is prime).

%Y Cf. A057197, A144487.

%K nonn

%O 1,1

%A _Vincenzo Librandi_, Apr 13 2012