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 A121176 #9 May 10 2022 10:29:13
%S A121176 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,17,18,19,20,21,22,23,24,26,28,29,
%T A121176 30,31,33,34,35,37,38,39,40,41,42,43,44,46,47,51,52,53,55,56,57,58,59,
%U A121176 60,61,62,65,66,67,68,69,70,71,73,74,76,77,78,79,82,83,84,85,86,87,88,89,91,92
%N A121176 Union of {8, 9, 18}, S, 2S and 4S, where S = squarefree numbers (A005117).
%C A121176 The asymptotic density of this sequence is 15/(2*Pi^2) (A323669). - _Amiram Eldar_, May 10 2022
%H A121176 Amiram Eldar, <a href="/A121176/b121176.txt">Table of n, a(n) for n = 1..10000</a>
%t A121176 Union[Join[{9, 18}, Select[Range[100], (e = IntegerExponent[#,2]) <= 3 && SquareFreeQ[#/2^e] &]]] (* _Amiram Eldar_, May 10 2022 *)
%Y A121176 Cf. A005117, A121684, A323669.
%K A121176 nonn
%O A121176 1,2
%A A121176 _N. J. A. Sloane_, Sep 13 2006