cp's OEIS Frontend

A302572 Unitary barely deficient numbers: unitary deficient numbers k such that usigma(k)/k > usigma(m)/m for all unitary deficient numbers m < k, where usigma(k) is the sum of the unitary divisors of k (A034448).

%I A302572 #13 Jul 21 2021 00:44:28
%S A302572 1,2,10,84,110,1155,6490,34320,55335,80652,163212,449295,676390,
%T A302572 1360810,1503370,1788490,3214090,22627605,32062485,35604492,103712410,
%U A302572 365690892,615206030,815634435
%N A302572 Unitary barely deficient numbers: unitary deficient numbers k such that usigma(k)/k > usigma(m)/m for all unitary deficient numbers m < k, where usigma(k) is the sum of the unitary divisors of k (A034448).
%e A302572 The values of usigma(k)/k are 1, 1.5, 1.8, 1.904..., 1.963..., 1.994...
%t A302572 usigma[n_] := If[n == 1, 1, Times @@ (1 + Power @@@ FactorInteger[n])]; seq = {}; r = 0; Do[s = usigma[n]/n; If[s < 2 && s > r, AppendTo[seq, n]; r = s], {n, 1, 1000000}]; seq
%Y A302572 Cf. A034448, A071927, A302570.
%K A302572 nonn,more
%O A302572 1,2
%A A302572 _Amiram Eldar_, Apr 10 2018