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 A026447 #12 Feb 07 2025 20:03:04
%S A026447 3,4,5,6,7,8,9,10,11,12,13,15,16,18,19,21,24,25,27,28,31,33,36,39,40,
%T A026447 43,45,48,49,51,53,55,60,61,63,64,69,70,71,73,75,76,81,84,85,87,88,89,
%U A026447 91,94,96,99,100,103,104,105,108,109,111,113
%N A026447 a(n) = least positive integer > a(n-1) and not a(i)*a(j)+2 for 1<=i<j<=n, with initial terms 3,4.
%H A026447 Ivan Neretin, <a href="/A026447/b026447.txt">Table of n, a(n) for n = 1..1000</a>
%t A026447 a = {3, 4}; 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 A026447 Cf. A026443 and references therein.
%K A026447 nonn
%O A026447 1,1
%A A026447 _Clark Kimberling_
%E A026447 Name clarified by _Robert C. Lyons_, Feb 07 2025