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Search: id:A082707
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| A082707 |
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Plateau and depression primes of the form 5*(10^a(n)-1)/9-2*(10^[ a(n)-1 ]+1) or (32*10^[ a(n)-1 ]-23)/9 or 32*(10^[ a(n)-1 ]-1)/9+1. |
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+0
2
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| 3, 9, 141, 231, 427, 463, 727, 1975, 7231, 45861, 47305
(list; graph; listen)
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OFFSET
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0,1
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COMMENT
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Prime versus probable prime status and proofs are given in the author's table.
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REFERENCES
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C. Caldwell and H. Dubner, "Journal of Recreational Mathematics", Volume 28, No. 1, 1996-97, pp. 1-9.
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LINKS
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P. De Geest, PDP Reference Table
Makoto Kamada, Factorizations of 355...553.
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EXAMPLE
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a(n)=9 -> 5*(10^9-1)/9-2*(10^8+1) = 355555553.
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CROSSREFS
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Cf. A082697 up to A082720.
Adjacent sequences: A082704 A082705 A082706 this_sequence A082708 A082709 A082710
Sequence in context: A082606 A062702 A141143 this_sequence A087193 A101967 A078590
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KEYWORD
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nonn,base
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AUTHOR
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Patrick De Geest (pdg(AT)worldofnumbers.com), Apr 13 2003.
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EXTENSIONS
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More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008
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