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 A325442 #4 May 02 2019 16:04:10
%S A325442 1,2,4,5,8,10,11,13,14,16,17,18,20,22,23,26,28,29,32,34,36,37,38,40,
%T A325442 41,44,46,47,49,50,52,53,56,58,59,61,62,64,65,68,70,72,74,76,77,80,82,
%U A325442 83,85,86,88,89,90,92,94,95,98,100,101,104,106,107,109,110
%N A325442 a(n) is the least number not 2*a(m)-1 or 3*a(m) for any m < n.
%H A325442 Clark Kimberling, <a href="/A325442/b325442.txt">Table of n, a(n) for n = 1..10000</a>
%e A325442 The sequence necessarily starts with 1. The next 2 terms are determined as follows: because a(1) = 1, the number 3 is disallowed, so that a(2) = 2, whence the numbers 3 and 6 are disallowed, and a(3) = 4. See A325417 for a guide to related sequences.
%t A325442 a = {1}; Do[AppendTo[a, NestWhile[# + 1 &, Last[a] + 1, Apply[Or,
%t A325442 Map[MemberQ[a, #] &, Select[Flatten[{(#+1)/2, #/3}],
%t A325442 IntegerQ]]] &]], {150}]; a (* A325442 *)
%t A325442 Complement[Range[Last[a]], a] (* A325443 *)
%t A325442 (* _Peter J. C. Moses_, Apr 25 2019 *)
%Y A325442 Cf. A325417, A325443.
%K A325442 nonn,easy
%O A325442 1,2
%A A325442 _Clark Kimberling_, May 02 2019