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A075818
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Even numbers with exactly 3 prime factors (counted with multiplicity).
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1
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8, 12, 18, 20, 28, 30, 42, 44, 50, 52, 66, 68, 70, 76, 78, 92, 98, 102, 110, 114, 116, 124, 130, 138, 148, 154, 164, 170, 172, 174, 182, 186, 188, 190, 212, 222, 230, 236, 238, 242, 244, 246, 258, 266, 268, 282, 284, 286, 290, 292, 310, 316, 318, 322, 332, 338
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Twice the semiprime numbers. [From Juri-Stepan Gerasimov (2stepan(AT)rambler.ru), Jun 01 2010]
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FORMULA
| a(n)=2*A001358(n). [From Juri-Stepan Gerasimov (2stepan(AT)rambler.ru), Jun 01 2010]
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EXAMPLE
| 28=2^2*7, 30=2*3*5 and 42=2*3*7 are even and are products of exactly 3 primes.
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MAPLE
| ts_bo3_sod := proc(n); if (numtheory[bigomega](n)=3 and type(n, even)='true') then RETURN(n); fi end: abo3sod := [seq(ts_bo3_sod(i), i=1..2300)]: abo3sod;
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CROSSREFS
| Cf. A046470, A053858.
Sequence in context: A066428 A187042 A054397 * A090738 A085103 A157940
Adjacent sequences: A075815 A075816 A075817 * A075819 A075820 A075821
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KEYWORD
| easy,nonn
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AUTHOR
| Jani Melik (jani_melik(AT)hotmail.com), Oct 13 2002
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EXTENSIONS
| Edited by Dean Hickerson (dean.hickerson(AT)yahoo.com), Oct 21 2002
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