A365074 Numbers k such that k! - k^2 - 1 is prime.

4, 6, 14, 126, 184, 634, 1354, 1550, 6710

Offset: 1

Author

Darío Clavijo, Sep 12 2023

Keywords

• nonn
• hard
• more

Crossrefs

Cf. A073443.

Programs

Mathematica

Select[Range[4, 1600, 2], PrimeQ[#! - #^2 - 1] &] (* Amiram Eldar, Sep 12 2023 *)

Python

from gmpy2 import *
print([k for k in range(0,2000) if is_prime((fac(k)- k*k - 1))])

Extensions

a(9) from Michael S. Branicky, Sep 14 2023