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A103068
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Numbers n such that 8*10^n-9 is prime.
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1
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1, 5, 11, 12, 17, 28, 46, 48, 61, 73, 138, 178, 213, 405, 762, 1053, 1157, 1427, 2865, 3148, 3615, 13447, 48081
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| Also numbers n such that 7*10^n + 9*R_n - 8 is prime, where R_n = 11...1 is the repunit (A002275) of length n.
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LINKS
| Makoto Kamada, Factorizations of 799...991.
Index entries for primes involving repunits.
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MATHEMATICA
| Do[ If[ PrimeQ[8*10^n - 9], Print[n]], {n, 0, 10000}]
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CROSSREFS
| Sequence in context: A102175 A139200 A102181 * A176821 A070369 A104215
Adjacent sequences: A103065 A103066 A103067 * A103069 A103070 A103071
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KEYWORD
| more,nonn
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AUTHOR
| Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 19 2005
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EXTENSIONS
| a(22)-a(23) from Kamada data by Robert Price (pamandbobprice(AT)yahoo.com), Dec 14 2010
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