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A080213
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a(n) = binomial(n, greatest prime factor of n).
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2
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1, 1, 1, 6, 1, 20, 1, 28, 84, 252, 1, 220, 1, 3432, 3003, 120, 1, 816, 1, 15504, 116280, 705432, 1, 2024, 53130, 10400600, 2925, 1184040, 1, 142506, 1, 496, 193536720, 2333606220, 6724520, 7140, 1, 35345263800, 8122425444, 658008, 1, 26978328, 1
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OFFSET
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1,4
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COMMENTS
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For n>1: a(n)=1 iff n is prime.
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LINKS
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Table of n, a(n) for n=1..43.
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FORMULA
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a(n) = binomial(n, A006530(n)). - Michel Marcus, May 06 2020
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MATHEMATICA
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Table[Binomial[n, FactorInteger[n][[-1, 1]]], {n, 50}] (* Harvey P. Dale, Feb 25 2015 *)
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PROG
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(PARI) a(n) = if (n==1, 1, binomial(n, vecmax(factor(n)[, 1]))); \\ Michel Marcus, May 06 2020
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CROSSREFS
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Cf. A006530, A080211, A080212.
Sequence in context: A064083 A152249 A167580 * A200091 A180733 A334504
Adjacent sequences: A080210 A080211 A080212 * A080214 A080215 A080216
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KEYWORD
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nonn
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AUTHOR
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Reinhard Zumkeller, Feb 06 2003
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STATUS
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approved
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