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A082715
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Plateau and depression primes of the form 8*(10^a(n)-1)/9-(10^[ a(n)-1 ]+1) or (71*10^[ a(n)-1 ]-17)/9.
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1
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OFFSET
| 1,1
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COMMENTS
| Prime versus probable prime status and proofs are given in the author's table.
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REFERENCES
| C. Caldwell and H. Dubner, "Journal of Recreational Mathematics", Volume 28, No. 1, 1996-97, pp. 1-9.
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LINKS
| P. De Geest, PDP Reference Table
Makoto Kamada, Prime numbers of the form 788...887.
Index entries for primes involving repunits.
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EXAMPLE
| a(n)=7 -> 8*(10^7-1)/9-(10^6+1) = 7888887.
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CROSSREFS
| Cf. A082697-A082720.
Sequence in context: A045974 A001531 A064118 * A041705 A137130 A058379
Adjacent sequences: A082712 A082713 A082714 * A082716 A082717 A082718
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KEYWORD
| nonn
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AUTHOR
| Patrick De Geest (pdg(AT)worldofnumbers.com), Apr 13 2003.
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EXTENSIONS
| 115811 from Ray Chandler (rayjchandler(AT)sbcglobal.net), Aug 05 2011
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