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 A325425 #10 Apr 28 2019 20:08:12
%S A325425 1,3,5,8,9,11,14,15,17,19,20,23,24,26,27,29,31,32,33,35,37,41,42,44,
%T A325425 45,47,50,51,53,56,57,59,60,65,68,69,71,72,73,77,78,80,81,83,86,87,89,
%U A325425 91,92,93,95,96,98,99,101,104,105,107,110,111,113,116,119
%N A325425 a(n) is the least number not 2*a(m) or floor(3*a(m)/2) for any m < n.
%C A325425 The sequence necessarily starts with 1. The next 2 terms are determined as follows: because a(1) = 1, the number 2 is disallowed, so that a(2) = 3, whence the numbers 4 and 6 are disallowed, and a(3) = 5. See A325417 for a guide to related sequences.
%H A325425 Clark Kimberling, <a href="/A325425/b325425.txt">Table of n, a(n) for n = 1..10000</a>
%t A325425 a = {1}; Do[AppendTo[a, NestWhile[# + 1 &, Last[a] + 1, Apply[Or,
%t A325425 Map[MemberQ[a, #] &, Select[Flatten[{#/2,
%t A325425 If[Mod[#, 3] == 0, (2 #)/3, 0] + If[Mod[#, 3] == 1, 1/3 (1 + 2 #), 0]}],
%t A325425 IntegerQ || # == 0]]] &]], {150}]; a (* A325425 *)
%t A325425 Complement[Range[Last[a]], a]; (* A325426 *)
%t A325425 (* _Peter J. C. Moses_, Apr 25 2019 *)
%Y A325425 Cf. A325417, A325426.
%K A325425 nonn,easy
%O A325425 1,2
%A A325425 _Clark Kimberling_, Apr 27 2019