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 A026454 #12 Mar 06 2016 06:51:11
%S A026454 1,3,4,5,6,7,8,9,11,12,14,15,17,20,21,23,24,27,29,32,35,36,37,39,41,
%T A026454 44,45,47,48,50,51,55,56,57,59,60,62,63,65,69,71,72,74,76,77,80,81,84,
%U A026454 87,89,91,92,93,95,99,101,102,104,105,107
%N A026454 a(n) = least positive integer > a(n-1) and not equal to a(i)*a(j)-2 for 1<=i<j<=n.
%H A026454 Ivan Neretin, <a href="/A026454/b026454.txt">Table of n, a(n) for n = 1..1000</a>
%t A026454 a = {1, 3}; used = {a[[1]]*a[[2]] - 2}; Do[k = a[[-1]] + 1; While[MemberQ[used, k], k++]; used = Union[used, k*a - 2]; AppendTo[a, k], {n, 3, 60}]; a (* _Ivan Neretin_, Mar 06 2016 *)
%Y A026454 Cf. A026453 and references therein.
%K A026454 nonn
%O A026454 1,2
%A A026454 _Clark Kimberling_
%E A026454 Definition corrected by _Harvey P. Dale_, Jun 12 2013