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 A309308 #8 Jul 27 2019 06:23:49
%S A309308 1,12,60,420,4620,360,1021020,19399380,446185740,13860,401120980260,
%T A309308 2520,608500527054420,26165522663340060,180180,65178316954380089460,
%U A309308 3845520700308425278140,234576762718813941966540,15716643102160534111758180,27720,3063060,6435289534681345815798169108260
%N A309308 Least number k with A309004(k) = n.
%F A309308 a(k) <= A088860(k).
%e A309308 a(3) = 60 since 60 is the least number with 3 numbers having the same prime signature and set of distinct prime factor as 60: 60 = 2^2 * 3 * 5, 90 = 3^2 * 2 * 5, and 150 = 5^2 * 2 * 3.
%t A309308 a[n_] := Multinomial @@ Tally[FactorInteger[n][[;;,2]]][[;;,2]]; m = 6; s = Table[0, {m}]; c = 0; n = 1; While[c < m, i = a[n]; If[i <= m && s[[i]] == 0, s[[i]] = n; c++]; n++]; s
%Y A309308 Cf. A088860, A111470, A309004.
%Y A309308 Subsequence of A025487.
%K A309308 nonn
%O A309308 1,2
%A A309308 _Amiram Eldar_, Jul 22 2019