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Search: id:A064814
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| A064814 |
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Greatest common divisor of n and the n-th composite number. |
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+0
7
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| 1, 2, 1, 1, 5, 6, 7, 1, 1, 2, 1, 3, 1, 2, 5, 2, 1, 2, 1, 4, 3, 2, 1, 12, 1, 13, 1, 14, 1, 15, 1, 16, 1, 2, 1, 4, 1, 1, 1, 1, 1, 6, 1, 1, 1, 1, 1, 4, 1, 10, 3, 2, 1, 2, 11, 2, 1, 1, 1, 12, 1, 2, 3, 8, 5, 1, 1, 1, 1, 5, 1, 2, 1, 2, 3, 4, 7, 2, 1, 10, 3, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 31, 1, 1, 32, 1, 2
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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a(12) = GCD(12, A002808(12)) = GCD(12, 21) = GCD(2*2*3, 3*7) = 3.
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LINKS
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R. Zumkeller, Table of n, a(n) for n = 1..10000 [From Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Jun 22 2009]
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FORMULA
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a(n) = GCD(n, A002808(n))
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PROGRAM
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(PARI) nextComp(n)= { if (!isprime(n), return(n)); return(n + 1) } { c=3; for (n=1, 1000, c=nextComp(c + 1); write("b064814.txt", n, " ", gcd(n, c)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Sep 27 2009]
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CROSSREFS
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Cf. A002808, A071224.
Sequence in context: A052916 A156576 A092437 this_sequence A051012 A064644 A090210
Adjacent sequences: A064811 A064812 A064813 this_sequence A064815 A064816 A064817
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KEYWORD
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nice,nonn
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AUTHOR
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Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Oct 22 2001
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