|
%I #25 Jan 21 2023 18:16:16
%S 3,5,7,13,29,61,383,401,1637,1871,36229,44771,44797,75167
%N Primes p such that (4^p - 2^p + 1)/3 is prime.
%C Terms > 1871 correspond to probable primes.
%e 3 is a term because 3 is prime and (4^3 - 2^3 + 1)/3 = 19 is also prime.
%o (PARI) isok(p)={isprime(p) && p>2 && ispseudoprime((4^p - 2^p + 1)/3)}
%o { forprime(p=3, 2000, if(isok(p), print1(p, ", "))) } \\ _Andrew Howroyd_, Dec 31 2022
%Y Cf. A000978.
%K nonn,more,hard
%O 1,1
%A _Jorge Coveiro_, Dec 31 2022
|
