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A052369
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Largest prime factor of n, where n runs through composite numbers.
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25
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2, 3, 2, 3, 5, 3, 7, 5, 2, 3, 5, 7, 11, 3, 5, 13, 3, 7, 5, 2, 11, 17, 7, 3, 19, 13, 5, 7, 11, 5, 23, 3, 7, 5, 17, 13, 3, 11, 7, 19, 29, 5, 31, 7, 2, 13, 11, 17, 23, 7, 3, 37, 5, 19, 11, 13, 5, 3, 41, 7, 17, 43, 29, 11, 5, 13, 23, 31, 47, 19, 3, 7, 11, 5, 17, 13, 7, 53, 3, 11, 37, 7, 19, 23
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OFFSET
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1,1
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LINKS
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FORMULA
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EXAMPLE
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First composite is 4, largest prime factor is 2, so a(1)=2.
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MAPLE
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map(t -> max(numtheory:-factorset(t)), remove(isprime, [$2..10^3])); # Robert Israel, Aug 10 2014
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MATHEMATICA
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FactorInteger[#][[-1, 1]]&/@Select[Range[150], CompositeQ] (* Harvey P. Dale, Jan 24 2016 *)
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PROG
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(Magma) [ D[ #D]: n in [2..115] | not IsPrime(n) where D is PrimeDivisors(n) ]; // [Klaus Brockhaus, Jun 23 2009]
(PARI) forcomposite(n=1, 1e2, p=factor(n)[omega(n), 1]; print1(p, ", ")) \\ Felix Fröhlich, Aug 08 2014
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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Michael Contente (mec1000(AT)aol.com), Mar 08 2000
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EXTENSIONS
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STATUS
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approved
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