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A071416
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GCD(n, binomial(2*n, n)).
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2
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1, 2, 1, 2, 1, 6, 1, 2, 1, 2, 1, 4, 1, 2, 15, 2, 1, 6, 1, 20, 3, 2, 1, 12, 1, 2, 1, 28, 1, 2, 1, 2, 3, 2, 7, 4, 1, 2, 1, 20, 1, 42, 1, 4, 45, 2, 1, 12, 1, 2, 3, 4, 1, 6, 1, 8, 3, 2, 1, 12, 1, 2, 3, 2, 5, 66, 1, 4, 3, 10, 1, 36, 1, 2, 15, 4, 77, 6, 1, 20, 1, 2, 1, 28, 5, 2, 3, 88, 1, 10, 91, 4, 1, 2, 5
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| a(n) = n for n in A014847. - Reinhard Zumkeller
a(n) = gcd(n, C(n)), C(n) the Catalan numbers. - Peter Luschny Oct 06 2011
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LINKS
| T. D. Noe, Table of n, a(n) for n=1..1000
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EXAMPLE
| a(10) = GCD(10, binomial(20, 10)) = GCD(10, 184756) = 2.
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MATHEMATICA
| Table[GCD[n, Binomial[2n, n]], {n, 100}] (* From Harvey P. Dale, Nov 10 2011 *)
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CROSSREFS
| Cf. A000984, A000108.
Sequence in context: A152823 A086545 A126083 * A053589 A055770 A113766
Adjacent sequences: A071413 A071414 A071415 * A071417 A071418 A071419
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KEYWORD
| nonn,nice
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AUTHOR
| Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), May 29 2002
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