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%I #12 Aug 03 2018 11:01:58
%S 0,5,64,691,7011,70030,699597,7005450,70048740,700321813,7003128054,
%T 70034216605,700350142296,7003426996800,70033987968599,
%U 700341098675985,7003416399263312
%N Number of unitary abundant numbers < 10^n.
%F Conjecture: Lim_{n->oo} a(n)/10^n = 0.07... is the density of unitary abundant numbers.
%t usigma[n_] := If[n == 1, 1, Times @@ (1 + Power @@@ FactorInteger[n])]; uabQ[n_] := usigma[n] > 2 n; c = 0; k = 1; seq={}; Do[While[k < 10^n, If[uabQ[k], c++]; k++]; AppendTo[seq, c], {n, 1, 5}]; seq
%Y Cf. A034448, A034683, A302992.
%K nonn,more
%O 1,2
%A _Amiram Eldar_, Apr 17 2018
%E a(10)-a(17) from _Hiroaki Yamanouchi_, Aug 03 2018
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