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A103033
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Numbers n such that 6*10^n + 3*R_n + 4 is prime, where R_n = 11...1 is the repunit (A002275) of length n.
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1
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1, 3, 4, 5, 6, 10, 13, 58, 96, 178, 360, 420, 455, 1008, 1517, 2975, 3999, 5425, 10819, 16036, 32076, 47237
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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 (19*10^n+11)/3 is prime.
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LINKS
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Table of n, a(n) for n=1..22.
Makoto Kamada, Prime numbers of the form 633...337.
Index entries for primes involving repunits.
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FORMULA
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a(n) = A101526(n) + 1.
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MATHEMATICA
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Do[ If[ PrimeQ[(19*10^n + 11)/3], Print[n]], {n, 0, 10000}]
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CROSSREFS
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Cf. A002275, A101526.
Sequence in context: A174057 A335231 A164977 * A099561 A110300 A143713
Adjacent sequences: A103030 A103031 A103032 * A103034 A103035 A103036
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KEYWORD
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more,nonn
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AUTHOR
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Robert G. Wilson v, Jan 18 2005
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EXTENSIONS
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Addition of a(19)-a(20) from Kamada data by Robert Price, Dec 10 2010
a(21)-a(22) from Erik Branger May 01 2013 by Ray Chandler, Aug 16 2013
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STATUS
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approved
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