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A102994
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Numbers n such that 4*10^n + 6*R_n - 5 is prime, where R_n = 11...1 is the repunit (A002275) of length n.
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3
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1, 2, 7, 9, 14, 24, 45, 49, 73, 74, 232, 338, 397, 504, 1063, 2817, 5305, 16768, 27060
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OFFSET
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1,2
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COMMENTS
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Also numbers n such that (14*10^n-17)/3 is prime.
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LINKS
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FORMULA
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MATHEMATICA
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Do[ If[ PrimeQ[(14*10^n - 17)/3], Print[n]], {n, 0, 10000}]
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CROSSREFS
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KEYWORD
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more,nonn
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AUTHOR
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EXTENSIONS
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Addition of a(18)-a(19) from Kamada data by Robert Price, Dec 10 2010
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STATUS
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approved
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