A109132 Numbers n such that n! + 1 is a Chen prime. n! + 1 is then called a factorial Chen prime.

0, 1, 2, 3, 11, 77

Offset: 1

Author

Jason Earls, Aug 17 2005

Keywords

• hard
• more
• nonn

Comments

Conjecture: 77! + 1 is the largest factorial Chen prime.

For n>2, n is in the sequence iff both numbers n!/3+1 and n!+1 are primes. - Farideh Firoozbakht, Mar 24 2006

Crossrefs

Cf. A002981, A109611.