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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}. 0
 6, 4560, 13770, 111552, 256011840 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS EXAMPLE NPPSigma(2^5*7^4)=(1+2+2^4)*(1+7+7^4)=45771 13770=2*3^4*5*17 so NPPSigma(2*3^4*5*17)=(1+2^1)*(1+3^1+3^4)*(1+5^1)*(1+17^1)=2*13770. Factorizations : 2*3, 2^4*3*5*19, 13770=2*3^4*5*17, 2^6*3*7*83, ... 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.