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 A227243 #24 Feb 16 2025 08:33:20 %S A227243 4,8,9,16,36,72,108,144,216,900,1800,2700,3600,44100,88200 %N A227243 Powerful numbers n such that n/phi(n) >= e^gamma*log log n. %C A227243 The sequence is complete. %H A227243 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/TotientFunction.html">Totient Function</a> %H A227243 <a href="/index/Pow#powerful">Index entries for sequences related to powerful numbers</a> %F A227243 A001694 INTERSECT A100966. %t A227243 PowerfulQ[1] := True; PowerfulQ[n_Integer?Positive] := Min[Last /@ FactorInteger[n]] > 1; Select[Range[100], PowerfulQ[#] && #/EulerPhi[#] >= E^EulerGamma*Log[Log[#]] &] (* _G. C. Greubel_, Oct 02 2017 *) %o A227243 (PARI) a=exp(Euler); for(n=4, 88200, if(ispowerful(n)&&n/eulerphi(n)>=a*log(log(n)), print1(n, ", "))); %Y A227243 Cf. A001694, A100966. %K A227243 nonn,easy,fini,full %O A227243 1,1 %A A227243 _Arkadiusz Wesolowski_, Oct 20 2013