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Search: id:A050299
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| A050299 |
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Numbers n such that ((n-1)!+1)/n is prime. |
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+0
4
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OFFSET
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1,2
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COMMENT
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Except for the first term, all terms are primes because for n > 1, n divides (n-1)!+1 iff n is prime. There are no other terms up to 6550 and the corresponding next prime has more than 22150 digits.
No more terms below 30941.
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REFERENCES
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Javier Soria, posting to Number Theory List, Apr 08 2003
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LINKS
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Mike Oakes, posting to Number Theory List, Aug 20 2003
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EXAMPLE
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7 is in the sequence because (6!+1)/7=103 is prime.
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MATHEMATICA
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v={1}; Do[If[PrimeQ[((Prime[n]-1)!+1)/Prime[n]], v=Append[v, Prime[n]]; Print[v]], {n, 845}]
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CROSSREFS
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Sequence in context: A157437 A031134 A144231 this_sequence A092029 A156559 A018426
Adjacent sequences: A050296 A050297 A050298 this_sequence A050300 A050301 A050302
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com), Apr 09 2003
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EXTENSIONS
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1321 and 2621 from Mike Oakes, Aug 20 2003
Additional comments from Farideh Firoozbakht (mymontain(AT)yahoo.com), Mar 19 2004
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