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A272621
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Numbers n such that 10^n-9^(n-1) is prime.
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0
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3, 9, 15, 155, 217, 281, 287, 491, 563, 581, 983, 2243, 4375, 8409, 98669
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OFFSET
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1,1
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COMMENTS
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a(16) > 10^5.
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LINKS
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EXAMPLE
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3 is a member since 10^3-9^2 = 1000-81 = 919 which is a prime number.
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MATHEMATICA
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Select[Range[0, 100000], PrimeQ[10^# - 9^(# - 1)] &]
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PROG
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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STATUS
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approved
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