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A087020
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Greatest prime factor of n-th cyclic number.
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6
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37, 5882353, 333667, 513239, 121499449, 11111111111111111111111, 154083204930662557781201849, 39526741, 9999999900000001, 59779577156334533866654838281, 119968369144846370226083377, 8396862596258693901610602298557167100076327481
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| A004042(n) factorized with Dario Alpern's ECM.
Extended using factors of 10^(A001913(n)-1)-1, see Kamada link.
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LINKS
| Ray Chandler, Table of n, a(n) for n = 1..42
Dario A. Alpern, Factorization using the Elliptic Curve Method.
Makoto Kamada, Factorizations of 11...11 (Repunit)
Eric Weisstein's World of Mathematics, Cyclic Number
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FORMULA
| a(n) = A006530(A004042(n+1)).
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EXAMPLE
| A004042(2) = 142857 = 37*13*11*3^3, therefore a(1) = 37.
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CROSSREFS
| Cf. A001913, A087021-A087026.
Sequence in context: A015037 A140746 A063681 * A171407 A023930 A022072
Adjacent sequences: A087017 A087018 A087019 * A087021 A087022 A087023
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KEYWORD
| nonn
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AUTHOR
| Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Jul 30 2003
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EXTENSIONS
| a(12)-a(42) from Ray Chandler (rayjchandler(AT)sbcglobal.net), Nov 16 2011
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