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A173718
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Numbers n such that (9^n - 2^n)/7 is prime.
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2
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2, 3, 5, 13, 29, 37, 1021, 1399, 2137, 4493, 5521, 108553, 200807
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OFFSET
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1,1
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COMMENTS
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All terms are prime.
a(14) > 10^6.
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LINKS
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MATHEMATICA
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Select[ Prime[ Range[1, 100000] ], PrimeQ[ (9^# - 2^#)/7 ]& ]
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PROG
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CROSSREFS
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Cf. A004063, A028491, A057468, A059801, A121877, A128024, A128025, A128026, A128027, A128028, A128029, A128030, A128031, A128032.
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KEYWORD
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hard,more,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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