A346168 Primes p such that p*p! - 1 is prime.

2, 3, 5, 7, 11, 397, 599, 2239

Offset: 1

Author

Reza K Ghazi, Jul 08 2021

Keywords

• nonn
• more

Comments

a(9) > 10^4.

Crossrefs

Prime terms of A090704.

Cf. A001563, A090703, A188914, A346167.

Programs

Maple

select(p -> isprime(p) and isprime(p*factorial(p) - 1), [$2 .. 600])

Mathematica

Select[Range[2, 600], PrimeQ[#] && PrimeQ[#*#! - 1] &]
Select[Prime[Range[110]],PrimeQ[# #!-1]&] (* The program generates the first 7 terms of the sequence. *) (* Harvey P. Dale, Feb 12 2025 *)

PARI

a = List(); for(p=2, 600, if(isprime(p) && isprime(p*p!-1), listput(a, p))); a

Sage

[p for p in range(2, 600) if is_prime(p) and is_prime(p*factorial(p) - 1)]