id:A115957 - OEIS Search Results

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Numbers n having exactly 3 distinct prime factors, the largest of which is greater than or equal to sqrt(n) (i.e. sqrt(n)-rough numbers with exactly 3 distinct prime factors).

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42, 66, 78, 102, 110, 114, 130, 138, 156, 170, 174, 186, 190, 204, 222, 228, 230, 238, 246, 255, 258, 266, 276, 282, 285, 290, 310, 318, 322, 342, 345, 348, 354, 366, 370, 372, 402, 406, 410, 414, 426, 430, 434, 435, 438, 444, 460, 465, 470, 474, 483, 492 (list; graph; listen)

	OFFSET	`1,1`
	EXAMPLE	`156 is in the sequence because it has 3 distinct prime factors (2, 3 and 13)` `and 13>sqrt(156).`
	MAPLE	`with(numtheory): a:=proc(n) if nops(factorset(n))=3 and factorset(n)[3]^2>=n then n else fi end: seq(a(n), n=1..530);`
	CROSSREFS	`Cf. A115956, A115958, A115959, A115960, A115961.` `Sequence in context: A053323 A119650 A118074 this_sequence A043689 A043573 A043733` `Adjacent sequences: A115954 A115955 A115956 this_sequence A115958 A115959 A115960`
	KEYWORD	`nonn`
	AUTHOR	`Emeric Deutsch (deutsch(AT)duke.poly.edu), Feb 02 2006`

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Last modified December 21 10:15 EST 2009. Contains 171081 sequences.

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