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Search: id:A047728
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| A047728 |
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Intersection of A046985 and A007691: multiply perfect, refactorable numbers with integer average divisor dividing the number. |
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1
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OFFSET
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1,2
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COMMENT
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Colton proves (link in A033950) that perfect numbers (A000396) cannot be refactorable.
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FORMULA
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All of these four quotients are integers: s1/s0, (x*s0)/s1, s1/x, x/s0.
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EXAMPLE
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x=45532800, s0=Sigma[ 0,x ]=384, s1=Sigma[ 1,x ]=571963392; Four quotients are all integral: a=s1/s0=474300, b=x/a=96, c=s1/x=4 and q=x/s0=118580.
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CROSSREFS
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Cf. A000396, A046985, A001599, A007691.
Adjacent sequences: A047725 A047726 A047727 this_sequence A047729 A047730 A047731
Sequence in context: A057796 A057797 A057802 this_sequence A124942 A064963 A059745
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KEYWORD
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nonn
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu)
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