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A059622
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Numbers k such that (5*3^k - 7)/2 is prime.
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1
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2, 4, 16, 24, 32, 40, 120, 124, 144, 172, 186, 376, 700, 1232, 1264, 2894, 5054, 14826, 16498, 18348, 33416
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OFFSET
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1,1
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COMMENTS
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LINKS
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MATHEMATICA
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Do[ If[ PrimeQ[ (5*3^n - 7)/2 ], Print[n] ], {n, 0, 10000} ]
Select[Range[5100], PrimeQ[(5*3^#-7)/2]&] (* Harvey P. Dale, Jul 15 2018 *)
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PROG
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(Magma) [k: k in [0..1000] | IsPrime((5*3^k - 7) div 2)]; // Jinyuan Wang, Jan 28 2020
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CROSSREFS
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Cf. A059621 ((5*3^k+7)/2 is prime).
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KEYWORD
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nonn,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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