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a(n) = least positive integer > a(n-1) and not a(i)*a(j)-2 for 1<=i<=j<=n.
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%I #11 Oct 30 2018 08:52:04

%S 3,4,5,6,8,9,11,12,15,17,19,20,21,24,26,27,29,32,33,35,36,37,39,40,41,

%T 44,45,47,48,50,51,54,56,57,59,60,63,65,67,68,69,71,72,75,77,80,81,84,

%U 87,89,90,91,92,95,96,99,101,104,105,107

%N a(n) = least positive integer > a(n-1) and not a(i)*a(j)-2 for 1<=i<=j<=n.

%C Essentially the same as A026460. [From _R. J. Mathar_, Oct 23 2008]

%H Christopher R. H. Hanusa, T Zaslavsky, S Chaiken, <a href="http://arxiv.org/abs/1609.00853">A q-Queens Problem. IV. Queens, Bishops, Nightriders (and Rooks)</a>, arXiv preprint arXiv:1609.00853, a12016

%t a[1] = 3; a[2] = 4; a[n_] := a[n] =

%t For[k = a[n-1]+1, True, k++, a[n] = k; If[AllTrue[Tuples[Range[n], {2}], k != a[#[[1]]] a[#[[2]]] - 2&], Return[k]]

%t ];

%t Array[a, 60] (* _Jean-François Alcover_, Oct 30 2018 *)

%K nonn

%O 1,1

%A _Clark Kimberling_