%I #9 May 10 2022 10:29:13

%S 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 30,31,33,34,35,37,38,39,40,41,42,43,44,46,47,51,52,53,55,56,57,58,59,

%U 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 Union of {8, 9, 18}, S, 2S and 4S, where S = squarefree numbers (A005117).

%C The asymptotic density of this sequence is 15/(2*Pi^2) (A323669). - _Amiram Eldar_, May 10 2022

%H Amiram Eldar, <a href="/A121176/b121176.txt">Table of n, a(n) for n = 1..10000</a>

%t Union[Join[{9, 18}, Select[Range[100], (e = IntegerExponent[#,2]) <= 3 && SquareFreeQ[#/2^e] &]]] (* _Amiram Eldar_, May 10 2022 *)

%Y Cf. A005117, A121684, A323669.

%K nonn

%O 1,2

%A _N. J. A. Sloane_, Sep 13 2006