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A081711
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Numbers k such that k! + k# - 1 is prime, where k# is the primorial function.
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3
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2, 3, 4, 5, 8, 17, 23, 26, 35, 47, 82, 100, 147, 183, 271, 492, 708, 1116, 1538, 2491, 4207, 4468
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OFFSET
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1,1
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COMMENTS
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Some of the larger entries may only correspond to probable primes.
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LINKS
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Mike Oakes, Primo-factorials, message 12028 in primenumbers Yahoo group, Apr 3, 2003. [Cached copy]
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EXAMPLE
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a(1)=2 because 2!+2#-1=3 is prime
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CROSSREFS
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KEYWORD
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nonn,more,hard
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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