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 A104026 #17 Feb 13 2021 01:11:39
%S A104026 32,72,108,128,200,243,288,384,392,432,486,500,512,600,675,800,864,
%T A104026 972,1125,1152,1176,1323,1350,1372,1440,1536,1568,1728,1944,1960,2000,
%U A104026 2048,2187,2250,2400,2560,2592,2646,2700,2904,3087,3125,3200,3240,3267,3380
%N A104026 Numbers that can be represented as k^2*j, 0 < j <= k but not if gcd(k, j) = 1.
%C A104026 The complement of A104020 and A104021.
%e A104026 32 is in the list because 32 = 4^2*2 but gcd(4,2) = 2.
%t A104026 A104020 = Take[Union[Flatten[Table[k^2 * j, {k, 70}, {j, k - 1}]]], 200]; A104021 = Take[Union[Flatten[Table[If[GCD[k, j] == 1, k^2 * j, {}], {k, 70}, {j, k - 1}]]], 150]; Complement[A104020, A104021]
%Y A104026 Cf. A104020, A104021.
%K A104026 nonn
%O A104026 1,1
%A A104026 _Leroy Quet_ and _Robert G. Wilson v_, Feb 25 2005