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 A325522 #7 May 06 2019 21:23:09
%S A325522 1,2,1,3,1,1,1,3,3,1,1,1,2,1,3,3,2,1,3,1,1,1,2,1,3,1,2,2,1,3,3,2,1,3,
%T A325522 1,1,1,3,3,1,2,2,1,3,1,1,1,2,1,3,1,1,1,3,3,1,1,1,2,1,3,2,1,2,1,3,1,1,
%U A325522 1,3,3,1,2,2,1,3,3,2,1,3,1,1,1,3,3,1
%N A325522 Difference sequence of A325429.
%C A325522 See A325417 for a guide to related sequences. Conjecture: every term is in {1,2,3}.
%H A325522 Clark Kimberling, <a href="/A325522/b325522.txt">Table of n, a(n) for n = 1..10000</a>
%t A325522 a = {1}; Do[AppendTo[a, NestWhile[# + 1 &, Last[a] + 1, Apply[Or,
%t A325522 Map[MemberQ[a, #] &, Select[Flatten[{#/3,
%t A325522 If[Mod[#, 3] == 0, (2 #)/3, 0] + If[Mod[#, 3] == 1, 1/3 (1 + 2 #), 0]}],
%t A325522 IntegerQ || # == 0]]] &]], {20000}]; a ; (* A325429 *)
%t A325522 c = Complement[Range[Last[a]], a] ; (* A325430 *)
%t A325522 Differences[a] (* A325522 *)
%t A325522 Differences[c] (* A325523 *)
%t A325522 (* _Peter J. C. Moses_, Apr 23 2019 *)
%Y A325522 Cf. A325417, A325429, A325523.
%K A325522 nonn,easy
%O A325522 1,2
%A A325522 _Clark Kimberling_, May 06 2019