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A103317
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Primes p such that p! - 1 is also prime.
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3
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OFFSET
| 1,1
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COMMENTS
| The members are the primes in A002982 (n! - 1 is prime).
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REFERENCES
| R. K. Guy, Unsolved Problems in Number Theory, Section A2.
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LINKS
| Eric Weisstein's World of Mathematics, Factorial Prime
Index entries for sequences related to factorial numbers.
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EXAMPLE
| 3 is prime and 3! - 1 = 5 is prime, so 3 is a member.
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MATHEMATICA
| Select[Prime[Range[100]], PrimeQ[#! - 1] &] (* From Vladimir Joseph Stephan Orlovsky, Feb 01 2012 *)
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CROSSREFS
| Cf. A002982.
Sequence in context: A088097 A064774 A089689 * A104051 A128004 A086559
Adjacent sequences: A103314 A103315 A103316 * A103318 A103319 A103320
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KEYWORD
| hard,more,nonn,changed
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AUTHOR
| Jonathan Sondow (jsondow(AT)alumni.princeton.edu), Jan 31 2005
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