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A103088
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Numbers k such that 8*10^k + 6*R_k + 3 is prime, where R_k = 11...1 is the repunit (A002275) of length k.
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1
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0, 1, 3, 17, 19, 33, 39, 169, 453, 611, 883, 1473, 6511, 9647, 21593, 39991, 40157, 71503
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OFFSET
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1,3
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COMMENTS
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Also numbers k such that (26*10^k+7)/3 is prime.
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LINKS
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FORMULA
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a(n) = A101075(n-1) + 1 for n >= 2.
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MATHEMATICA
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Do[ If[ PrimeQ[(26*10^k + 7)/3], Print[k]], {k, 0, 10000}]
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CROSSREFS
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KEYWORD
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more,nonn,changed
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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