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A258357
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Numbers n such that cyclotomic polynomial value Phi(7,n!) is prime.
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1
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OFFSET
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1,3
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COMMENTS
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Except for the values 0,1,2 and 3, terms correspond to probable primes.
a(8) > 6502.
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LINKS
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EXAMPLE
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3 is in the sequence because Phi(7,3!) = 1 + 6 + 6^2 + 6^3 + 6^4 + 6^5 + 6^6 = 55987 is prime.
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MATHEMATICA
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Select[Range[0, 6502], PrimeQ[Cyclotomic[7, #!]] &]
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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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STATUS
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approved
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