OFFSET
1,1
COMMENTS
REFERENCES
R. K. Guy, Unsolved Problems in Number Theory, Section A2.
LINKS
R. Mestrovic, Euclid's theorem on the infinitude of primes: a historical survey of its proofs (300 BC--2012) and another new proof, arXiv preprint arXiv:1202.3670, 2012 - From N. J. A. Sloane, Jun 13 2012
Eric Weisstein's World of Mathematics, Factorial Prime
EXAMPLE
2 and 2! + 1 = 3 are prime, so 3 is a member.
MATHEMATICA
Select[Table[p!+1, {p, Prime[Range[30]]}], PrimeQ] (* Harvey P. Dale, Nov 28 2019 *)
CROSSREFS
KEYWORD
hard,nonn
AUTHOR
Jonathan Sondow, Jan 31 2005
STATUS
approved