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%I #27 Nov 21 2019 15:00:46
%S 1333,1909,2469601,893748277,322685352001,8992165119733,
%T 42052982615431201
%N 18-hyperperfect numbers: n = 18*(sigma(n)-n-1) + 1.
%C 1978419655654505210563957 are also terms. - _Donovan Johnson_, Nov 20 2012
%C a(8) > 10^17. - _Max Alekseyev_, Nov 17 2019
%H Judson S. McCranie, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL3/mccranie.html">A Study of Hyperperfect Numbers</a>, Journal of Integer Sequences, Vol. 3 (2000), Article 00.1.3.
%Y Cf. A000396, A007593, A220290, A028499, A028500, A028502, A034916.
%K hard,more,nonn
%O 1,1
%A _Jud McCranie_
%E a(5) from _Donovan Johnson_, Nov 03 2011
%E a(6)-a(7) from _Donovan Johnson_ confirmed by _Max Alekseyev_, Nov 21 2019
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