A064595 Nontrivial nonunitary multiply perfect numbers: the sum of the nonunitary divisors of n is a positive multiple of n; i.e., (sigma(n) - usigma(n))/n is a positive integer.

24, 112, 1984, 2520, 31320, 32512, 1163160, 2208384, 3053232, 6535296, 13472928, 123165600, 134201344, 186076800, 365959296, 3456573120, 4401782352, 5517818880, 18924364800, 34359476224, 325377803520

Offset

1,1

Links

Table of n, a(n) for n=1..21.

Mathematica

nusigma[ n_ ] := DivisorSigma[ 1, n ]-Times@@(1+Power@@#&/@FactorInteger[ n ]); For[ n=1, True, n++, v=nusigma[ n ]; If[ v>0&&Mod[ v, n ]==0, Print[ n ] ] ]

Crossrefs

Cf. A048146, A064591, A064592, A064593, A064594, A064596.

Sequence in context: A307859 A263542 A281133 * A064591 A228433 A124952

Adjacent sequences: A064592 A064593 A064594 * A064596 A064597 A064598

Keyword

nonn,hard

Author

Dean Hickerson, Sep 25 2001

Status

approved