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a(n) = least positive integer > a(n-1) and not a(i)*a(j)+2 for i<=1<=j<=n.
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%I #8 Mar 06 2016 04:34:21

%S 2,3,4,5,7,9,13,15,19,21,24,25,26,31,33,34,35,36,39,42,43,45,46,48,49,

%T 53,55,56,57,58,60,61,63,66,69,71,73,75,76,79,81,82,84,85,87,89,90,91,

%U 96,99,103,105,109,111,113,115,117,120,121

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

%H Ivan Neretin, <a href="/A026450/b026450.txt">Table of n, a(n) for n = 1..1000</a>

%t a = {2, 3}; used = {a[[1]]^2 + 2, a[[1]]*a[[2]] + 2, a[[2]]^2 + 2}; Do[k = a[[-1]] + 1; While[MemberQ[used, k], k++]; AppendTo[a, k]; used = Union[used, k*a + 2], {n, 3, 60}]; a (* _Ivan Neretin_, Mar 06 2016 *)

%Y Cf. A026443 and references therein.

%K nonn

%O 1,1

%A _Clark Kimberling_