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A052369
Largest prime factor of n, where n runs through composite numbers.
26
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
OFFSET
1,1
LINKS
FORMULA
a(n) = A006530(A002808(n)). [Reinhard Zumkeller, Aug 25 2008]
EXAMPLE
First composite is 4, largest prime factor is 2, so a(1)=2.
MAPLE
map(t -> max(numtheory:-factorset(t)), remove(isprime, [$2..10^3])); # Robert Israel, Aug 10 2014
MATHEMATICA
FactorInteger[#][[-1, 1]]&/@Select[Range[150], CompositeQ] (* Harvey P. Dale, Jan 24 2016 *)
PROG
(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
CROSSREFS
Cf. A002808, A006530, A056608. [From Reinhard Zumkeller, Aug 25 2008]
Sequence in context: A046147 A251865 A306196 * A110976 A318271 A236483
KEYWORD
nonn,easy
AUTHOR
Michael Contente (mec1000(AT)aol.com), Mar 08 2000
EXTENSIONS
More terms from James A. Sellers, Mar 09 2000
STATUS
approved