OFFSET
1,2
COMMENTS
All the terms are odd squarefree numbers.
MATHEMATICA
Select[Range[1, 350, 2], PrimeQ[2*EulerPhi[#] + #] &] (* Amiram Eldar, Aug 17 2023 *)
PROG
(Python)
from sympy import totient, isprime
print([k for k in range(1, 340) if isprime(2*totient(k) + k)])
(PARI) isok(k) = isprime(k+2*eulerphi(k)); \\ Michel Marcus, Aug 20 2023
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Darío Clavijo, Aug 17 2023
STATUS
approved