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A064596
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Smallest nonunitary multiperfect number of index n; i.e. smallest k such that sigma(k) - usigma(k) = nk.
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5
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OFFSET
| 0,2
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COMMENTS
| 4.5*10^14 < a(4) <= 1081895452249824576000.
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MATHEMATICA
| nusigma[ n_ ] := DivisorSigma[ 1, n ]-Times@@(1+Power@@#&/@FactorInteger[ n ]); a[ n_ ] := For[ k=1, True, k++, If[ nusigma[ k ]==n k, Return[ k ] ] ]
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CROSSREFS
| Cf. A048146, A064591, A064592, A064593, A064594, A064595.
Sequence in context: A202927 A008977 A159392 * A092706 A060902 A090444
Adjacent sequences: A064593 A064594 A064595 * A064597 A064598 A064599
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KEYWORD
| nonn,hard,more
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AUTHOR
| Dean Hickerson (dean.hickerson(AT)yahoo.com), Sep 25, 2001
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