Primes of the form 3*2^k + 1.A039687Primes of the form 3*2^k + 1.Terms a(0) =7a(1) =13a(2) =97a(3) =193a(4) =769a(5) =12289a(6) =786433a(7) =3221225473a(8) =206158430209External referencesoeis: A039687