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A103000
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Numbers n such that 4*10^n + 8*R_n + 1 is prime, where R_n = 11...1 is the repunit (A002275) of length n.
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2
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0, 3, 4, 6, 10, 12, 18, 40, 48, 96, 106, 114, 144, 364, 618, 1090, 11370, 59454, 196684
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| Also numbers n such that (44*10^n+1)/9 is prime.
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LINKS
| Makoto Kamada, Factorizations of 488...889.
Index entries for primes involving repunits.
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MATHEMATICA
| Do[ If[ PrimeQ[(44*10^n + 1)/9], Print[n]], {n, 0, 10000}]
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CROSSREFS
| Sequence in context: A031132 A057477 A113887 * A074321 A167410 A085378
Adjacent sequences: A102997 A102998 A102999 * A103001 A103002 A103003
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KEYWORD
| more,nonn
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AUTHOR
| Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 17 2005
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EXTENSIONS
| Addition of a(16)-a(18) from Kamada data by Robert Price (pamandbobprice(AT)yahoo.com), Dec 10 2010
0 added by Arkadiusz Wesolowski (wesolowski(AT)aol.pl), Mar 10 2011
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