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Search: id:A066746
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| A066746 |
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Conjectured values of a(n) defined by a(n) = least number of applications of f(k) = k^2 + 1 to n to yield a prime, if this number exists; = -1 otherwise. |
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+0
1
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| 1, 0, 0, 1, 0, 1, 0, 3, -1, 1, 0
(list; graph; listen)
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OFFSET
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1,8
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COMMENT
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a(9) = -1 is conjectural. If a(9) is positive, then a(9) > 14. (f^15)(9) already has several thousand digits. (f^n denotes f applied n times.)
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EXAMPLE
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f(f(f(8))) = f(f(65)) = f(4226) = 17859077, a prime. Since 8, 65, 4226 are prime, then a(8) = 3.
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CROSSREFS
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Sequence in context: A114151 A110518 A006837 this_sequence A074063 A115717 A115718
Adjacent sequences: A066743 A066744 A066745 this_sequence A066747 A066748 A066749
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KEYWORD
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more,sign
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AUTHOR
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Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Jan 16 2002
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