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 A386977 #31 Aug 12 2025 18:00:45
%S A386977 216,240,336,360,504,528,540,560,600,624,756,792,810,816,840,880,900,
%T A386977 912,936,1000,1040,1104,1134,1176,1188,1224,1232,1260,1320,1350,1360,
%U A386977 1368,1392,1400,1404,1456,1488,1500,1520,1560,1656,1764,1776,1782,1836,1840,1848
%N A386977 Products of 3 distinct semiprimes.
%H A386977 Alois P. Heinz, <a href="/A386977/b386977.txt">Table of n, a(n) for n = 1..10000</a>
%e A386977 216 = 4 * 6 * 9.
%p A386977 q:= n-> (l-> l=[3$2] or nops(l)>2 and add(i, i=l)=6)(ifactors(n)[2][..., 2]):
%p A386977 select(q, [$1..2000])[]; # _Alois P. Heinz_, Aug 12 2025
%t A386977 Select[Range@ 2000, MemberQ[{{3,3}, {1,1,4}, {1,2,3}, {2,2,2}, {1,1,1,3}, {1,1,2,2}, {1,1,1,1,2}, {1,1,1,1,1,1}}, Sort[Last /@ FactorInteger@ #]] &] (* _Giovanni Resta_, Aug 12 2025 *)
%Y A386977 Cf. A001222, A001358 (semiprimes), A007304 (sphenic numbers).
%Y A386977 Subsequence of A046306.
%K A386977 nonn
%O A386977 1,1
%A A386977 _Ian Hahus_, Aug 11 2025