A113546 - OEIS

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A113546

Let S(n)=1/3*sigma(n). Numbers such that S(S(n))=n, 1/3-sociable number of order 1 or 2.

120, 672, 7680, 8184, 523776 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,1`
	COMMENTS	`a(1) and a(2) and a(5) are 3 multiple perfect numbers. a(4)=S(a(3)).`
	LINKS	`Eric Weisstein's World of Mathematics, Sociable Numbers`
	CROSSREFS	`Sequence in context: A152622 A100145 A090216 * A166069 A114887 A069085` `Adjacent sequences: A113543 A113544 A113545 * A113547 A113548 A113549`
	KEYWORD	`nonn`
	AUTHOR	`Yasutoshi Kohmoto zbi74583(AT)boat.zero.ad.jp, Jan 27 2006`

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Last modified February 16 12:15 EST 2012. Contains 205909 sequences.