A161003 A list of the composite numbers divided by their largest prime factors.

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

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: A317015 A341902 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