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 A381249 #14 Apr 27 2025 14:54:02
%S A381249 2,6,8,9,12,15,16,18,24,27,32,36,40,45,48,54,60,64,72,80,81,90,96,108,
%T A381249 120,128,135,144,160,162,180,192,216,240,243,270,288,320,324,360,384,
%U A381249 405,432,480,486,540,576,640,648,720,729,810,864,960,972,1024,1080,1152
%N A381249 Indices of records in k/A001414(k), k>=2.
%C A381249 Except for initial 2, this is a subsequence of A381972.
%e A381249 f(2) = 1 < f(6) = 6/5 < f(8) = 4/3 < f(9) = 3/2 < f(12) = 12/7, where f(k) = k/A001414(k).
%t A381249 z = 800; g[n_] := FactorInteger[n];
%t A381249 f[n_] := Map[First, g[n]] . Map[Last, g[n]];
%t A381249 mx = -1; k = 2; u = {}; While[k < z, a = k/f[k]; If[a > mx, mx = a; AppendTo[u, k]]; k++]; u
%o A381249 (PARI) sopfr(n) = (n=factor(n))[, 1]~*n[, 2];
%o A381249 lista(nn) = my(r=oo, list=List()); for (n=2, nn, my(x=sopfr(n)/n); if (x < r, listput(list, n); r = x)); Vec(list); \\ _Michel Marcus_, Apr 27 2025
%Y A381249 Cf. A001414, A082299, A082343, A082344, A381972.
%K A381249 nonn
%O A381249 1,1
%A A381249 _Clark Kimberling_, Apr 19 2025
%E A381249 More terms from _Michel Marcus_, Apr 27 2025