id:A143204 - OEIS Search Results

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Numbers with at least 2 and not more than 3 distinct prime factors not greater than 7 that are multiples of 7 or of 15.

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14, 28, 30, 56, 60, 90, 98, 112, 120, 150, 180, 196, 224, 240, 270, 300, 360, 392, 448, 450, 480, 540, 600, 686, 720, 750, 784, 810, 896, 900, 960, 1080, 1200, 1350, 1372, 1440, 1500, 1568, 1620, 1792, 1800, 1920, 2160, 2250, 2400, 2430, 2700, 2744, 2880 (list; graph; listen)

	OFFSET	`1,1`
	COMMENT	`A143201(a(n)) = 6;` `2<=A001221(a(n))<=3; A020639(a(n))=2; 5<=A006530(a(n))<=7;` `GCD(a(n),21)=1;` `union of A143207 and A033847.`
	EXAMPLE	`a(1) = 14 = 2 * 7 = A033847(1);` `a(2) = 28 = 2^2 * 7 = A033847(2);` `a(3) = 30 = 2 * 3 * 5 = A143207(1);` `a(4) = 56 = 2^3 * 7 = A033847(3);` `a(5) = 60 = 2^2 * 3 * 5 = A143207(2);` `a(6) = 90 = 2 * 3^2 * 5 = A143207(3);` `a(7) = 98 = 2 * 7^2 = A033847(4);` `a(8) = 112 = 2^4 * 7 = A033847(5);` `a(9) = 120 = 2^3 * 3 * 5 = A143207(4);` `a(10) = 150 = 2 * 3 * 5^2 = A143207(5);` `a(11) = 180 = 2^2 * 3^2 * 5 = A143207(6);` `a(12) = 196 = 2^2 * 7^2 = A033847(6).`
	CROSSREFS	`Sequence in context: A086451 A040182 A095782 this_sequence A118904 A164722 A162020` `Adjacent sequences: A143201 A143202 A143203 this_sequence A143205 A143206 A143207`
	KEYWORD	`nonn`
	AUTHOR	`Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Aug 12 2008`

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.

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