

A052369


Largest prime factor of n, where n runs through composite numbers.


25



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

1,1


LINKS

Robert Israel, Table of n, a(n) for n = 1..10000


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 FrÃ¶hlich, Aug 08 2014


CROSSREFS

Cf. A002808, A006530, A056608. [From Reinhard Zumkeller, Aug 25 2008]
Sequence in context: A046147 A251865 A306196 * A110976 A318271 A236483
Adjacent sequences: A052366 A052367 A052368 * A052370 A052371 A052372


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



