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A102979
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Numbers n such that 3*10^n + 8*R_n - 1 is prime, where R_n = 11...1 is the repunit (A002275) of length n.
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1
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OFFSET
| 1,3
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COMMENTS
| Also numbers n such that (35*10^n-17)/9 is prime.
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LINKS
| Makoto Kamada, Factorizations of 388...887.
Index entries for primes involving repunits.
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MATHEMATICA
| Do[ If[ PrimeQ[(35*10^n - 17)/9], Print[n]], {n, 0, 10000}]
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CROSSREFS
| Sequence in context: A137040 A172733 A088021 * A069942 A146202 A145720
Adjacent sequences: A102976 A102977 A102978 * A102980 A102981 A102982
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KEYWORD
| more,nonn
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AUTHOR
| Robert G. Wilson v (rgwv(AT)rgwv.com), Dec 17 2004
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EXTENSIONS
| Additional term 10176 (a PRP) from Serge Batalov (batalovs(AT)yahoo.com), Oct 12 2008
Addition of a(5) from Kamada data by Robert Price (pamandbobprice(AT)yahoo.com), Dec 13 2010
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