id:A080257 - OEIS Search Results

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Numbers having at least two distinct or a total of three prime factors.

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7

6, 8, 10, 12, 14, 15, 16, 18, 20, 21, 22, 24, 26, 27, 28, 30, 32, 33, 34, 35, 36, 38, 39, 40, 42, 44, 45, 46, 48, 50, 51, 52, 54, 55, 56, 57, 58, 60, 62, 63, 64, 65, 66, 68, 69, 70, 72, 74, 75, 76, 77, 78, 80, 81, 82, 84, 85, 86, 87, 88, 90, 91, 92, 93, 94, 95, 96, 98, 99, 100 (list; graph; listen)

	OFFSET	`1,1`
	COMMENT	`Complement of A000430; A080256(a(n)) > 3.` `A084114(a(n)) > 0, see also A084110.` `Also numbers greater than the square of their smallest prime-factor: a(n)>A020639(a(n))^2=A088377(a(n));` `a(n)>A000430(k) for n<=13, a(n)<A000430(k) for n>13.` `Numbers with at least 4 divisors. - Frank Adams-Watters (FrankTAW(AT)Netscape.net), Jul 28 2006`
	EXAMPLE	`8=222 and 10=25 are terms; 4=22 is not a term.`
	CROSSREFS	`Cf. A001248, A001221, A001222, A006881, A030078.` `Cf. A088381, A088383.` `Cf. A000005.` `Sequence in context: A071278 A079772 A080731 this_sequence A050199 A139118 A089229` `Adjacent sequences: A080254 A080255 A080256 this_sequence A080258 A080259 A080260`
	KEYWORD	`nonn`
	AUTHOR	`Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Feb 10 2003`

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Last modified December 9 18:50 EST 2009. Contains 170568 sequences.

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