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%I #11 Sep 29 2018 04:34:39
%S 186076800,3456573120,18924364800,325377803520,2666567816640,
%T 8538872307840,11169839116800
%N Nonunitary triply perfect numbers: the sum of the nonunitary divisors of n is 3n; i.e., sigma(n) - usigma(n) = 3n.
%C There are no others up to 1.6*10^13, but there are at least 20 larger ones, between 87916260096000 and 19424258892617980729341453189120.
%C Ligh & Wall found a(1), a(4) and a(5). - _Amiram Eldar_, Sep 27 2018
%H Steve Ligh and Charles R. Wall, <a href="https://www.fq.math.ca/Scanned/25-4/ligh.pdf">Functions of Nonunitary Divisors</a>, Fibonacci Quarterly, Vol. 25 (1987), pp. 333-338.
%Y Cf. A048146, A064591, A064592, A064594, A064595, A064596.
%K nonn,hard
%O 1,1
%A _Dean Hickerson_, Sep 25 2001
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