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A099723
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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}.
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OFFSET
| 1,1
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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, ...
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CROSSREFS
| Cf. A096290.
Sequence in context: A110106 A024087 A161845 * A066061 A028366 A115431
Adjacent sequences: A099720 A099721 A099722 * A099724 A099725 A099726
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KEYWORD
| nonn
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AUTHOR
| Yasutoshi Kohmoto (zbi74583(AT)boat.zero.ad.jp), Nov 06, 2004
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EXTENSIONS
| Corrected and extended by Farideh Firoozbakht (mymontain(AT)yahoo.com), Nov 07 2004
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