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A046339
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Composite numbers with an odd number of prime factors (counted with multiplicity).
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4
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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; refs; listen; history; internal format)
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OFFSET
| 1,1
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EXAMPLE
| a(1)=8 as 8=2*2*2, that is 8 is a composite integer and having 3 (an odd number) prime factors.
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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)
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CROSSREFS
| Cf. A046340, A046341, A026424.
Sequence in context: A036327 A051144 A067537 * A145784 A014612 A046369
Adjacent sequences: A046336 A046337 A046338 * A046340 A046341 A046342
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KEYWORD
| nonn
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AUTHOR
| Patrick De Geest (pdg(AT)worldofnumbers.com), Jun 15 1998.
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