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 A103317 Primes p such that p! - 1 is also prime. 3
 3, 7, 379, 6917 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The members are the primes in A002982 (n! - 1 is prime). REFERENCES R. K. Guy, Unsolved Problems in Number Theory, Section A2. LINKS Eric Weisstein's World of Mathematics, Factorial Prime EXAMPLE 3 is prime and 3! - 1 = 5 is prime, so 3 is a member. MATHEMATICA Select[Prime[Range[100]], PrimeQ[#! - 1] &] (* Vladimir Joseph Stephan Orlovsky, Feb 01 2012 *) CROSSREFS Cf. A002982. Sequence in context: A064774 A089689 A248701 * A104051 A128004 A281889 Adjacent sequences:  A103314 A103315 A103316 * A103318 A103319 A103320 KEYWORD hard,more,nonn AUTHOR Jonathan Sondow, Jan 31 2005 STATUS approved

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Last modified December 10 14:50 EST 2018. Contains 318049 sequences. (Running on oeis4.)