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A102944
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Numbers k such that 10^k + 8*R_k - 5 is prime, where R_k = 11...1 is the repunit (A002275) of length k.
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1
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1, 16, 22, 28, 34, 90, 2068, 2374, 2854, 3720, 4242, 22666, 29292, 29508
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OFFSET
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1,2
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COMMENTS
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Also numbers k such that (17*10^k - 53)/9 is prime.
a(15) > 10^5. - Robert Price, Feb 11 2015
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LINKS
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Table of n, a(n) for n=1..14.
Makoto Kamada, Prime numbers of the form 188...883.
Index entries for primes involving repunits.
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FORMULA
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a(n) = A102030(n) + 1.
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MATHEMATICA
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Do[ If[ PrimeQ[(17*10^n - 53)/9], Print[n]], {n, 0, 10000}]
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CROSSREFS
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Cf. A002275, A102030.
Sequence in context: A294125 A341169 A064804 * A058901 A059756 A242214
Adjacent sequences: A102941 A102942 A102943 * A102945 A102946 A102947
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KEYWORD
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more,nonn
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AUTHOR
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Robert G. Wilson v, Dec 16 2004
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EXTENSIONS
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Addition of a(12)-a(14) from Kamada data by Robert Price, Dec 12 2010
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STATUS
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approved
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