%I #13 Mar 07 2016 10:24:29

%S 3,4,5,6,7,8,10,11,13,14,17,19,22,23,26,27,29,31,34,37,38,41,43,45,46,

%T 47,53,54,58,59,61,62,63,67,71,72,73,74,75,79,82,83,86,89,90,94,96,97,

%U 99,101,103,105,106,107,109,113,117,118,120,122,125,126,127,128,131,134

%N a(n) = least positive integer > a(n-1) and not equal to a(i)*a(j) for 1<=i<=j<=n.

%C Starting from 3, include only those numbers that aren't the product of two numbers already included.

%C Numbers >3 not included: 9,12,15,18,21,24,30,33,39,42,51,57,66,69,78,....

%H Ivan Neretin, <a href="/A026427/b026427.txt">Table of n, a(n) for n = 1..1000</a>

%e 9 is excluded because 9=3*3. 10 is included because 10 is not the product of any two of 3,4,5,6,7,8.

%t f[s_List] := Block[{k = s[[ -1]] + 1, ss = Times @@@ Tuples[s, 2]}, While[MemberQ[ss, k], k++ ]; Append[s, k]]; Nest[f, {3}, 65] (* _Robert G. Wilson v_ Sep 23 2006 *)

%Y Cf. A066680.

%Y Cf. A026416 and references therein.

%K nonn

%O 1,1

%A _Clark Kimberling_

%E Edited by _N. J. A. Sloane_, Sep 14 2008 at the suggestion of _R. J. Mathar_