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 A325541 #4 May 07 2019 23:14:57
%S A325541 1,2,2,1,3,1,1,4,1,1,1,3,2,2,1,1,1,1,1,3,2,4,1,1,1,1,2,1,1,3,1,2,4,2,
%T A325541 2,2,1,1,1,3,1,1,3,1,1,1,1,3,2,4,2,1,3,2,2,1,1,1,1,4,1,1,3,1,1,1,1,1,
%U A325541 2,1,1,3,1,2,1,3,2,4,1,1,1,3,2,3,1,1
%N A325541 Difference sequence of A325539.
%C A325541 See A325417 for a guide to related sequences. Conjecture: every term is in {1,2,3,4}.
%H A325541 Clark Kimberling, <a href="/A325541/b325541.txt">Table of n, a(n) for n = 1..10000</a>
%t A325541 a = {1}; Do[AppendTo[a, NestWhile[# + 1 &, Last[a] + 1,
%t A325541 Apply[Or, Map[MemberQ[a, #] &, Select[Flatten[{(# - 1)/2, (# - 2)/3}],
%t A325541 IntegerQ]]] &]], {200}]; a (* A325539 *)
%t A325541 Complement[Range[Last[a]], a] (* A325540 *)
%t A325541 Differences[a] (* A325541 *)
%t A325541 Differences[c] (* A325542 *)
%t A325541 (*_Peter J. C. Moses_, Apr 23 2019*)
%Y A325541 Cf. A325417, A325539, A325542.
%K A325541 nonn,easy
%O A325541 1,2
%A A325541 _Clark Kimberling_, May 07 2019