OFFSET
1,1
MATHEMATICA
Select[Range[4, 1600, 2], PrimeQ[#! - #^2 - 1] &] (* Amiram Eldar, Sep 12 2023 *)
PROG
(Python)
from gmpy2 import *
print([k for k in range(0, 2000) if is_prime((fac(n)- k*k - 1))])
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
Darío Clavijo, Sep 12 2023
EXTENSIONS
a(9) from Michael S. Branicky, Sep 14 2023
STATUS
approved