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Search: id:A100473
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| A100473 |
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Numbers n such that 9*10^n + R_n + 6 is prime, where R_n = 11...1 is the repunit (A002275) of length n. |
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+0
3
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| 1, 17, 23, 73, 131, 473, 685, 701, 1909, 3029, 3473, 4193, 9931
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Also numbers n such that (82*10^n+53)/9 is a prime.
Some of the larger entries may only correspond to probable primes.
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LINKS
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Makoto Kamada, Factorizations of 911...117.
Index entries for primes involving repunits.
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EXAMPLE
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n = 1, 17, so that 97 and 911111111111111117 are primes.
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MATHEMATICA
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Do[ If[ PrimeQ[(82*10^n + 53)/9], Print[n]], {n, 0, 10000}] (from Robert G. Wilson v Jan 19 2005)
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CROSSREFS
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Sequence in context: A039319 A043142 A043922 this_sequence A060252 A127924 A108260
Adjacent sequences: A100470 A100471 A100472 this_sequence A100474 A100475 A100476
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KEYWORD
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more,nonn
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AUTHOR
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Julien Peter Benney (jpbenney(AT)ftml.net), Nov 21 2004
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EXTENSIONS
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a(8)- a(12) from Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 12 2005
a(13) from Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 12 2005
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