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 A325519 #7 May 06 2019 21:23:44
%S A325519 2,2,1,3,2,1,3,2,3,1,3,3,2,4,2,2,1,1,3,3,2,1,3,2,1,3,3,1,1,1,2,1,3,4,
%T A325519 1,1,3,3,2,1,3,2,4,3,3,2,1,3,2,1,3,2,1,2,1,2,1,3,5,1,3,3,2,1,3,2,2,1,
%U A325519 1,3,3,2,1,3,2,3,1,3,3,2,4,4,1,1,2,1
%N A325519 Difference sequence of A325426.
%C A325519 See A325417 for a guide to related sequences. Conjecture: every term is in {1,2,3,4,5,6,7}.
%H A325519 Clark Kimberling, <a href="/A325519/b325519.txt">Table of n, a(n) for n = 1..10000</a>
%t A325519 a = {1}; Do[AppendTo[a, NestWhile[# + 1 &, Last[a] + 1, Apply[Or,
%t A325519 Map[MemberQ[a, #] &, Select[Flatten[{#/2,
%t A325519 If[Mod[#, 3] == 0, (2 #)/3, 0] + If[Mod[#, 3] == 1, 1/3 (1 + 2 #), 0]}],
%t A325519 IntegerQ || # == 0]]] &]], {200}]; a ; (* A325425 *)
%t A325519 c = Complement[Range[Last[a]], a] ; (* A325426 *)
%t A325519 Differences[a] (* A325518 *)
%t A325519 Differences[c] (* A325519 *)
%t A325519 (* _Peter J. C. Moses_, Apr 23 2019 *)
%Y A325519 Cf. A325417, A325426, A325518.
%K A325519 nonn,easy
%O A325519 1,1
%A A325519 _Clark Kimberling_, May 06 2019