This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A353038 #7 Apr 19 2022 07:26:37
%S A353038 90,40682250,81364500,105773850,423095400,1798155450,14385243600
%N A353038 Unitary harmonic numbers (A006086) that are not unitary arithmetic numbers (A103826).
%C A353038 There are 290 unitary harmonic numbers below 10^12, and only 7 of them are in this sequence.
%e A353038 90 is in the sequence since its unitary divisors are {1, 2, 5, 9, 10, 18, 45, 90}, their harmonic mean, 4, is an integer, but their arithmetic mean, 45/2, is not.
%t A353038 q[n_] := Module[{f = FactorInteger[n], d, s}, d = 2^Length[f]; s = Times @@ (1 + Power @@@ f); IntegerQ[n*d/s] && !IntegerQ[s/d]]; Select[Range[5*10^7], q]
%Y A353038 The unitary version of A046999.
%Y A353038 Subsequence of A006086.
%Y A353038 Cf. A006087, A103826.
%K A353038 nonn,more
%O A353038 1,1
%A A353038 _Amiram Eldar_, Apr 19 2022