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Search: id:A082713
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| A082713 |
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Plateau and depression primes of the form 5*(10^a(n)-1)/9+2*(10^[ a(n)-1 ]+1) or (68*10^[ a(n)-1 ]+13)/9. |
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+0 2
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| 3, 5, 11, 21, 23, 59, 75, 83, 209, 351, 423, 3813, 3983, 20925, 23787, 38853
(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 755...557.
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EXAMPLE
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a(n)=21 -> 5*(10^21-1)/9+2*(10^20+1) = 755555555555555555557.
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CROSSREFS
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Cf. A082697 up to A082720.
Sequence in context: A058932 A118037 A094588 this_sequence A074710 A057460 A045515
Adjacent sequences: A082710 A082711 A082712 this_sequence A082714 A082715 A082716
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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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