A113286 - OEIS

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A113286

Let S(n)=1/4*Sigma(n) . Numbers such that S(S(n))=n, 1/4-Sociable number of order 1 or 2.

30240, 32760, 859320, 898560 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,1`
	COMMENTS	`a(1) and a(2) are 4 multiple perfect numbers. a(4)=S(a(3)). I calculated {2096640,2234232}. It is unknown if any pair exists between {a(3),a(4)} and this pair.`
	LINKS	`Eric Weisstein's World of Mathematics, Sociable Numbers`
	CROSSREFS	`Cf. A113546.` `Sequence in context: A104877 A027665 A202598 * A027687 A190475 A109485` `Adjacent sequences: A113283 A113284 A113285 * A113287 A113288 A113289`
	KEYWORD	`nonn`
	AUTHOR	`Yasutoshi Kohmoto zbi74583(AT)boat.zero.ad.jp, Jan 27 2006`

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Last modified February 16 19:05 EST 2012. Contains 205944 sequences.