A099723 - OEIS

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A099723

Nonprime-power sigma-perfect numbers: numbers n such that NPPSigma(n)=2*n, where, if n=Product p_i^r_i then NPPSigma(n)=Product{Sum p_i^s_i, s_i is not a prime number, 0<=s_i<=r_i}.

6, 4560, 13770, 111552, 256011840 (list; graph; refs; listen; history; text; internal format)

	OFFSET	`1,1`
	LINKS	`Table of n, a(n) for n=1..5.`
	EXAMPLE	`NPPSigma(2^57^4)=(1+2+2^4)(1+7+7^4)=45771` `13770=23^4517 so NPPSigma(23^4517)=(1+2^1)(1+3^1+3^4)(1+5^1)(1+17^1)=213770.` `Factorizations : 23, 2^43519, 13770=23^4517, 2^63783, ...`
	CROSSREFS	`Cf. A096290.` `Sequence in context: A024087 A161845 A209310 * A066061 A028366 A115431` `Adjacent sequences: A099720 A099721 A099722 * A099724 A099725 A099726`
	KEYWORD	`nonn`
	AUTHOR	`Yasutoshi Kohmoto (zbi74583(AT)boat.zero.ad.jp), Nov 06, 2004`
	EXTENSIONS	`Corrected and extended by Farideh Firoozbakht, Nov 07 2004`
	STATUS	`approved`

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Last modified May 21 15:35 EDT 2013. Contains 225504 sequences.