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 A346574 #16 Jul 30 2021 08:31:26
%S A346574 1,120,1920,16320,32640,261120,1044480,8355840,26732160,67107840,
%T A346574 253955520,268431360,507911040,2147450880,4063288320,9396354240
%N A346574 Numbers k at which phi(tau(k))/tau(phi(k)) reaches a record high.
%H A346574 International Mathematical Olympiad, <a href="http://www.imo-official.org/problems/IMO2020SL.pdf">Problem N6</a>, IMO-2020, p. 81.
%t A346574 max=0;lst={};Do[t=EulerPhi[DivisorSigma[0,k]]/DivisorSigma[0,EulerPhi@k];If[t>max,AppendTo[lst,k];max=t],{k,100000}];lst (* _Giorgos Kalogeropoulos_, Jul 27 2021 *)
%o A346574 (PARI) lista(nn) = my(r, t); for(k=1, nn, if(r<t=eulerphi(numdiv(k))/numdiv(eulerphi(k)), r=t; print1(k, ", ")));
%Y A346574 Cf. A000005, A000010, A062821, A163109.
%K A346574 nonn,more
%O A346574 1,2
%A A346574 _Jinyuan Wang_, Jul 24 2021
%E A346574 a(14)-a(16) from _Amiram Eldar_, Jul 30 2021