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A261730
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Values of n such that prime(n)! - n! + 1 is a prime number.
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0
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OFFSET
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1,2
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COMMENTS
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Initial primes of the form prime(n)! - n! + 1 are 2, 5, 121645100408791681.
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LINKS
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EXAMPLE
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For n=1, prime(1)!-1!+1 = 2 is a prime number.
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MATHEMATICA
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Select[Range[400], PrimeQ[Prime[#]! - #! + 1] &] (* Vincenzo Librandi, Aug 31 2015 *)
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PROG
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(PARI) for(n=1, 1e3, if(isprime(prime(n)!-n!+1), print1(n", ")))
(Magma) [n: n in [1..80] | IsPrime(Factorial(NthPrime(n))-Factorial(n)+1)]; // Vincenzo Librandi, Aug 31 2015
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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