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 A026426 #8 Mar 07 2016 10:23:25
%S A026426 2,4,5,6,7,9,11,13,15,17,19,21,23,27,29,31,32,33,37,39,40,41,43,47,48,
%T A026426 50,51,53,56,57,59,61,67,69,70,71,72,73,79,83,87,88,89,93,97,98,101,
%U A026426 103,104,107,109,110,111,113,120,123,125,127
%N A026426 a(n) = least positive integer > a(n-1) and not a(i)*a(j) for 1<=i<=j<=n, n >= 2.
%H A026426 Ivan Neretin, <a href="/A026426/b026426.txt">Table of n, a(n) for n = 1..1000</a>
%t A026426 a = {2, 4}; used = {a[[1]]^2, a[[1]]*a[[2]], a[[2]]^2}; Do[k = a[[-1]] + 1; While[MemberQ[used, k], k++]; AppendTo[a, k]; used = Union[used, k*a], {n, 3, 66}]; a (* _Ivan Neretin_, Mar 07 2016 *)
%Y A026426 Cf. A026416 and references therein.
%K A026426 nonn
%O A026426 1,1
%A A026426 _Clark Kimberling_