Primes p of the form 2^k + 4*(-1)^k - 3.A269835Primes p of the form 2^k + 4*(-1)^k - 3.Terms a(0) =2a(1) =5a(2) =17a(3) =257a(4) =65537a(5) =549755813881External referencesoeis: A269835