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A128458
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Numbers k such that 15^k - 2 is a prime.
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13
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1, 2, 3, 7, 12, 17, 19, 51, 65, 550, 1460, 1641, 7035, 18002, 20963, 21163, 42563, 94906, 148048
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OFFSET
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1,2
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COMMENTS
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LINKS
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MATHEMATICA
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Do[ f = 15^n - 2; If[ PrimeQ[ f ], Print[ {n, f} ] ], {n, 1, 1000} ]
Do[If[PrimeQ[15^n - 2], Print[n]], {n, 10^4}] (* Ryan Propper, Jun 06 2007 *)
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CROSSREFS
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Cf. A084714 (smallest prime of the form (2n-1)^k - 2).
Cf. A128472 (smallest prime of the form (2n-1)^k - 2 for k > (2n-1)).
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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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