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Search: id:A087021
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| A087021 |
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Number of distinct prime factors of n-th cyclic number. |
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+0
4
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| 4, 8, 8, 8, 10, 8, 10, 21, 23, 19, 19
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OFFSET
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1,1
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COMMENT
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A004042(n) factorized with Dario Alpern's ECM;
a(n) = A001221(A004042(n)).
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LINKS
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Dario A. Alpern, Factorization using the Elliptic Curve Method.
Eric Weisstein's World of Mathematics, Cyclic Number
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EXAMPLE
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A004042(1) = 142857 = 37*13*11*3^3, therefore a(1) =
#{3,11,13,37} = 4.
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CROSSREFS
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Cf. A001913, A087022, A087023.
Adjacent sequences: A087018 A087019 A087020 this_sequence A087022 A087023 A087024
Sequence in context: A032566 A040012 A054006 this_sequence A029679 A141284 A072541
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KEYWORD
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nonn
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AUTHOR
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Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Jul 30 2003
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