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A168645
Numbers with 2 or 3 prime divisors (counted with multiplicity).
5
4, 6, 8, 9, 10, 12, 14, 15, 18, 20, 21, 22, 25, 26, 27, 28, 30, 33, 34, 35, 38, 39, 42, 44, 45, 46, 49, 50, 51, 52, 55, 57, 58, 62, 63, 65, 66, 68, 69, 70, 74, 75, 76, 77, 78, 82, 85, 86, 87, 91, 92, 93, 94, 95, 98, 99, 102, 105, 106, 110, 111, 114, 115, 116, 117, 118, 119
OFFSET
1,1
COMMENTS
Below 32 this sequence and A063989 are identical.
MATHEMATICA
Select[Range[150], MemberQ[{2, 3}, Total[Transpose[ FactorInteger[#]] [[2]]]]&] (* Harvey P. Dale, Mar 28 2011 *)
PROG
(PARI) is(n)=my(t=bigomega(n)); t==2 || t==3 \\ Charles R Greathouse IV, Jun 19 2016
CROSSREFS
Sequence in context: A063806 A323521 A063989 * A282668 A117097 A077135
KEYWORD
nonn
AUTHOR
STATUS
approved