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 A026437 #18 Feb 06 2025 13:51:37
%S A026437 1,2,4,5,6,8,10,12,13,14,16,17,18,20,21,22,26,28,30,32,34,36,37,38,40,
%T A026437 42,44,45,46,48,50,52,53,54,56,57,58,60,61,62,65,66,68,70,72,74,76,78,
%U A026437 80,81,82,85,86,88,90,92,93,94,96,97
%N A026437 a(n) = least positive integer > a(n-1) and not a(i)*a(j)-1 for 1 <= i <= j < n, n >= 2, with initial terms 1,2.
%H A026437 Ivan Neretin, <a href="/A026437/b026437.txt">Table of n, a(n) for n = 1..1000</a>
%t A026437 a = {1, 2}; used = Flatten@Outer[Times, a, a] - 1; Do[k = a[[-1]] + 1; While[MemberQ[used, k], k++]; AppendTo[a, k]; used = Union[used, k*a - 1], {n, 3, 60}]; a (* _Ivan Neretin_, Feb 15 2018 *)
%Y A026437 Similar sequences with different starting conditions: A026438 (1,3), A026439 (2,3), A026440 (1,4), A026441 (2,4), A026442 (3,4).
%Y A026437 Related sequences with definition using distinct i,j: A026431 and references therein.
%K A026437 nonn
%O A026437 1,2
%A A026437 _Clark Kimberling_
%E A026437 Terms corrected by _Ivan Neretin_, Feb 15 2018
%E A026437 Name clarified by _Robert C. Lyons_, Feb 06 2025