A346168 - OEIS

%I #26 Aug 16 2021 22:18:14

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

%N Primes p such that p*p! - 1 is prime.

%C a(9) > 10^4.

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

%t Select[Range[2, 600], PrimeQ[#] && PrimeQ[#*#! - 1] &]

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

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

%Y Prime terms of A090704.

%Y Cf. A001563, A090703, A188914, A346167.

%K nonn,more

%O 1,1

%A _Reza K Ghazi_, Jul 08 2021