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 A026427 #15 Jun 24 2025 13:27:43
%S A026427 3,4,5,6,7,8,10,11,13,14,17,19,22,23,26,27,29,31,34,37,38,41,43,45,46,
%T A026427 47,53,54,58,59,61,62,63,67,71,72,73,74,75,79,82,83,86,89,90,94,96,97,
%U A026427 99,101,103,105,106,107,109,113,117,118,120,122,125,126,127,128,131,134
%N A026427 a(n) = least positive integer > a(n-1) and not equal to a(i)*a(j) for 1<=i<=j<=n.
%C A026427 Starting from 3, include only those numbers that aren't the product of two numbers already included.
%C A026427 Numbers >3 not included: 9,12,15,18,21,24,30,33,39,42,51,57,66,69,78,....
%C A026427 Appears to be A026423 shifted left. - _R. J. Mathar_, Jun 24 2025
%H A026427 Ivan Neretin, <a href="/A026427/b026427.txt">Table of n, a(n) for n = 1..1000</a>
%e A026427 9 is excluded because 9=3*3. 10 is included because 10 is not the product of any two of 3,4,5,6,7,8.
%t A026427 f[s_List] := Block[{k = s[[ -1]] + 1, ss = Times @@@ Tuples[s, 2]}, While[MemberQ[ss, k], k++ ]; Append[s, k]]; Nest[f, {3}, 65] (* _Robert G. Wilson v_ Sep 23 2006 *)
%Y A026427 Cf. A066680.
%Y A026427 Cf. A026416 and references therein.
%K A026427 nonn
%O A026427 1,1
%A A026427 _Clark Kimberling_
%E A026427 Edited by _N. J. A. Sloane_, Sep 14 2008 at the suggestion of _R. J. Mathar_