Multifactorial numbers are of the form n!k
If k is even then n!k is odd for all odd n. Therefore n!k+/-1 are both even and hence not prime. In this case we can look for primes of the form n!k+/-2. However as these numbers are not +/-1 from a number that can be easily factored Brillhart-Lehmer-Selfridge is not a suitable test to prove primality. So other than for the small primes I have used Marcel Martin's Primo which implements the elliptical curve primality proving (ECPP) algorithm to prove numbers prime.
Certificates for Primo proofs are available on request.
|Type||nmaxtested||Digits of largest proven prime||Digits of largest prp||n is prime for:|