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A161003 A list of the composite numbers divided by their largest prime factors. 1
2, 2, 4, 3, 2, 4, 2, 3, 8, 6, 4, 3, 2, 8, 5, 2, 9, 4, 6, 16, 3, 2, 5, 12, 2, 3, 8, 6, 4, 9, 2, 16, 7, 10, 3, 4, 18, 5, 8, 3, 2, 12, 2, 9, 32, 5, 6, 4, 3, 10, 24, 2, 15, 4, 7, 6, 16, 27, 2, 12, 5, 2, 3, 8, 18, 7, 4, 3, 2, 5, 32, 14, 9, 20, 6, 8, 15, 2, 36, 10, 3, 16, 6, 5, 4, 9, 2, 7, 24, 11, 2, 3, 4 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(A120389(n)) = A000040(n). - Gionata Neri, May 07 2015

For n >= 2, a(x) = n where x = A066246(n*A006530(n)). - Robert Israel, May 07 2015

LINKS

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

FORMULA

a(n) = A002808(n)/A052369(n). - Robert Israel, May 07 2015

EXAMPLE

n=1 4/2; n=2 6/3; n=3 8/2.

MAPLE

with(numtheory): a := proc (n) if isprime(n) = false then n/factorset(n)[nops(factorset(n))] else end if end proc: seq(a(n), n = 2 .. 130); # Emeric Deutsch, Jun 27 2009

MATHEMATICA

With[{cmps=Select[Range[200], CompositeQ]}, #/FactorInteger[#][[-1, 1]]&/@ cmps] (* Harvey P. Dale, Mar 29 2017 *)

CROSSREFS

Cf. A000040, A002808, A006530, A052369, A066246, A120389, A161004, A160180.

Sequence in context: A306323 A317015 A175681 * A152028 A244318 A316774

Adjacent sequences:  A161000 A161001 A161002 * A161004 A161005 A161006

KEYWORD

nonn

AUTHOR

Trevor Cassiliano (casstjc(AT)gmail.com), Jun 01 2009

EXTENSIONS

Extended by Emeric Deutsch, Jun 27 2009

STATUS

approved

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Last modified May 25 07:29 EDT 2020. Contains 334584 sequences. (Running on oeis4.)