A144922 - OEIS

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A144922

Numbers n such that n*sigma_2(n)/sigma_1(n) is an integer

1, 4, 6, 9, 12, 16, 18, 20, 24, 25, 28, 36, 44, 45, 48, 49, 50, 54, 60, 64, 72, 81, 90, 92, 96, 100, 108, 112, 117, 121, 132, 140, 144, 150, 153, 162, 168, 169, 180, 192, 196 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	COMMENTS	`n*A001157(n)/A000203(n) is an integer. This sequence is connected closely with Ore divisor numbers (A001599) and RMS numbers (A140480).`
	CROSSREFS	`Cf. A000203, A001157, A001599, A140480` `Sequence in context: A024675 A163656 A100915 * A185595 A088765 A175250` `Adjacent sequences: A144919 A144920 A144921 * A144923 A144924 A144925`
	KEYWORD	`easy,nonn`
	AUTHOR	`Ctibor O. Zizka (c.zizka(AT)email.cz), Sep 25 2008`

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Last modified February 16 19:23 EST 2012. Contains 205945 sequences.