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 A307122 #7 Apr 29 2019 21:00:15
%S A307122 1,2,4,6,12,24,36,48,60,168,252,300,336,630,2268,2310,5472,6804,20412,
%T A307122 47424,61236,161304,183708,486096,551124,1215216,1653372,4081104,
%U A307122 4960116,14880348,44641044,133923132,401769396,1205308188,1631268870,3615924564,10847773692
%N A307122 3-deficient numbers with increasing abundancy: Numbers k such that sigma(m)/m < sigma(k)/k < 3 for all numbers m < k such that sigma(m)/m < 3.
%C A307122 Analogous to A259312 with 3-deficient numbers instead of 3-abundant numbers.
%C A307122 Analogous to A228450 with ratio 3 instead of 2.
%C A307122 The values of sigma(a(n))/a(n) are 1, 1.5, 1.75, 2, 2.333..., 2.5, 2.527..., 2.583..., 2.8, ...
%t A307122 sm=0; seq={}; Do[s=DivisorSigma[1,n]/n; If[s<3 && s>sm, sm=s; AppendTo[seq, n]], {n,1,100000}]; seq
%Y A307122 Cf. A071927, A023197, A228450, A259312.
%K A307122 nonn
%O A307122 1,2
%A A307122 _Amiram Eldar_, Mar 26 2019