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Primes of the form (5*4^k + 1)/3.
0

%I #17 Sep 04 2024 15:15:44

%S 2,7,107,6827,27962027,1789569707,114532461227,7870610804782742022827,

%T 37167908664217705235892863787747269176634027,

%U 9743344248872686121357898884775220131039550286507,623574031927851911766905528625614088386531218336427,46011642311937091916231705748513503016340726481135910367750161491995307

%N Primes of the form (5*4^k + 1)/3.

%C Primes in A136412.

%F { A000040 } intersect { A136412 }.

%e 107 is a term because it is a prime and (5*4^3 + 1)/3 = 107.

%p select(isprime, [(5*4^k+1)/3$k=0..120])[]; # _Alois P. Heinz_, Mar 01 2022

%t Select[(5*4^Range[0,200]+1)/3,PrimeQ] (* _Harvey P. Dale_, Sep 04 2024 *)

%Y Cf. A000040, A136412.

%K nonn

%O 1,1

%A _Patrick N. Valdivia_, Mar 01 2022