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A064593 Nonunitary triply perfect numbers: the sum of the nonunitary divisors of n is 3n; i.e., sigma(n) - usigma(n) = 3n. 4
186076800, 3456573120, 18924364800, 325377803520, 2666567816640, 8538872307840, 11169839116800 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..7.

CROSSREFS

Cf. A048146, A064591, A064592, A064594, A064595, A064596.

Sequence in context: A253941 A230222 A061440 * A084304 A228377 A178565

Adjacent sequences:  A064590 A064591 A064592 * A064594 A064595 A064596

KEYWORD

nonn,hard

AUTHOR

Dean Hickerson, Sep 25 2001

EXTENSIONS

There are no others up to 1.6*10^13, but there are at least 20 larger ones, between 87916260096000 and 19424258892617980729341453189120.

STATUS

approved

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Last modified February 23 22:59 EST 2018. Contains 299595 sequences. (Running on oeis4.)