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Search: id:A098959
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| A098959 |
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Numbers n such that 2*10^n + 6*R_n - 3 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, 2, 3, 5, 6, 7, 11, 21, 30, 68, 73, 169, 176, 345, 823, 1021, 1191, 2073, 2755, 10717, 14673, 16754, 17606
(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 (8*10^n-11)/3 is prime.
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LINKS
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Makoto Kamada, Factorizations of 266...663.
Index entries for primes involving repunits.
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EXAMPLE
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For n = 1, 2, 3, 5, 6, 7, we get 23, 263, 2663, 266663, 2666663 and
26666663 which are primes.
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MATHEMATICA
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Do[ If[ PrimeQ[(8*10^n - 11)/3], Print[n]], {n, 0, 10000}]
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CROSSREFS
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Sequence in context: A019438 A023798 A062084 this_sequence A071251 A077571 A101730
Adjacent sequences: A098956 A098957 A098958 this_sequence A098960 A098961 A098962
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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), Oct 21 2004
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EXTENSIONS
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a(15), a(16) & a(17) from Ray Chandler (rayjchandler(AT)sbcglobal.net), Nov 04 2004
a(18) & a(19) from Robert G. Wilson v (rgwv(AT)rgwv.com), Dec 17 2004
More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008
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