id:A046339 - OEIS Search Results

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Composite numbers with an odd number of prime factors (counted with multiplicity).

+0
5

8, 12, 18, 20, 27, 28, 30, 32, 42, 44, 45, 48, 50, 52, 63, 66, 68, 70, 72, 75, 76, 78, 80, 92, 98, 99, 102, 105, 108, 110, 112, 114, 116, 117, 120, 124, 125, 128, 130, 138, 147, 148, 153, 154, 162, 164, 165, 168, 170, 171, 172, 174, 175, 176, 180, 182, 186, 188 (list; graph; listen)

	OFFSET	`1,1`
	EXAMPLE	`a(1)=8 as 8=222, that is 8 is a composite integer and having 3 (an odd number) prime factors.`
	MATHEMATICA	`fQ[n_] := Block[{p = Plus @@ Last /@ FactorInteger@n}, OddQ[p] && p > 1]; Select[ Range@200, fQ[ # ] &] (from Robert G. Wilson v (rgwv(at)rgwv.com), Jan 04 2006)`
	CROSSREFS	`Cf. A046340, A046341, A026424.` `Sequence in context: A036327 A051144 A067537 this_sequence A145784 A014612 A046369` `Adjacent sequences: A046336 A046337 A046338 this_sequence A046340 A046341 A046342`
	KEYWORD	`nonn`
	AUTHOR	`Patrick De Geest (pdg(AT)worldofnumbers.com), Jun 15 1998.`

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Last modified December 20 16:54 EST 2009. Contains 171081 sequences.

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