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Search: id:A103048
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| A103048 |
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Numbers n such that 7*10^n-9 is prime. |
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+0
2
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| 1, 2, 3, 4, 14, 15, 23, 28, 54, 100, 272, 373, 403, 568, 639, 842, 969, 1255, 1259, 3047, 4838, 6389, 12755, 15142
(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 6*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
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Makoto Kamada, Factorizations of 699...991.
Index entries for primes involving repunits.
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MATHEMATICA
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Do[ If[ PrimeQ[7*10^n - 9], Print[n]], {n, 0, 10000}]
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CROSSREFS
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Sequence in context: A067177 A039576 A091907 this_sequence A140128 A100998 A127283
Adjacent sequences: A103045 A103046 A103047 this_sequence A103049 A103050 A103051
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KEYWORD
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more,nonn
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AUTHOR
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Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 18 2005
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EXTENSIONS
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More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 01 2008
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