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A046866
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Numbers k such that 6*7^k - 1 is prime.
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13
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0, 1, 2, 7, 18, 55, 69, 87, 119, 141, 189, 249, 354, 1586, 2135, 2865, 2930, 4214, 7167, 67485, 74402, 79326
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OFFSET
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1,3
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COMMENTS
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REFERENCES
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R. K. Guy, Unsolved Problems in Number Theory, Section A3.
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LINKS
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MATHEMATICA
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Do[ If[ PrimeQ[6*7^n - 1], Print[n]], {n, 0, 5650}]
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PROG
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(PARI) for(n=0, 2000, if(isprime(6*7^n-1), print1(n, ", ")))
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CROSSREFS
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KEYWORD
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nonn,hard,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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