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A089085
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Numbers k such that (k! + 3)/3 is prime.
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57
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3, 5, 6, 8, 11, 17, 23, 36, 77, 93, 94, 109, 304, 497, 1330, 1996, 3027, 3053, 4529, 5841, 20556, 26558, 28167
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OFFSET
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1,1
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COMMENTS
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a(21) > 20000. The PFGW program has been used to certify all the terms up to a(20), using the "N-1" deterministic test. - Giovanni Resta, Mar 31 2014
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LINKS
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MATHEMATICA
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PROG
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(Magma) [n: n in [0..500] | IsPrime((Factorial(n)+3) div 3)]; // Vincenzo Librandi, Dec 12 2011
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CROSSREFS
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Cf. n!/m-1 is a prime: A002982, A082671, A139056, A139199-A139205; n!/m+1 is a prime: A002981, A082672, A089085, A139061, A139058, A139063, A139065, A151913, A137390, A139071 (1<=m<=10).
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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1330 from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 03 2008
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STATUS
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approved
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