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A191469
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Numbers n such that 7^n - 6 is prime.
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11
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2, 3, 6, 9, 21, 25, 33, 49, 54, 133, 245, 255, 318, 1023, 1486, 3334, 6821, 8555, 11605, 42502, 44409, 90291, 92511, 140303
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OFFSET
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1,1
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COMMENTS
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a(14)=1023 and a(15)=1486 correspond to BPSW strong probable primes (passing PARI's ispseudoprime()). - Joerg Arndt, Jun 06 2011
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LINKS
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MAPLE
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MATHEMATICA
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PROG
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(Magma) [n: n in [1..1000]| IsPrime(7^n-6)]
(PARI) for(n=1, 10^6, if(isprime(7^n-6), 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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