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A046340
Odd composite numbers with an odd number of prime factors (counted with multiplicity).
4
27, 45, 63, 75, 99, 105, 117, 125, 147, 153, 165, 171, 175, 195, 207, 231, 243, 245, 255, 261, 273, 275, 279, 285, 325, 333, 343, 345, 357, 363, 369, 385, 387, 399, 405, 423, 425, 429, 435, 455, 465, 475, 477, 483, 507, 531, 539, 549, 555, 561, 567, 575
OFFSET
1,1
MATHEMATICA
Select[Range[3, 699, 2], OddQ[Total[Transpose[FactorInteger[#]][[2]]]] && !PrimeQ[#]&] (* Harvey P. Dale, Dec 09 2010 *)
Select[Range[3, 699, 2], CompositeQ[#]&&OddQ[PrimeOmega[#]]&] (* Harvey P. Dale, Jun 18 2024 *)
CROSSREFS
Sequence in context: A259504 A307373 A121614 * A046316 A046373 A228057
KEYWORD
nonn
AUTHOR
Patrick De Geest, Jun 15 1998
EXTENSIONS
Name (description) modified by Harvey P. Dale, Dec 09 2010
STATUS
approved