%I #7 May 06 2019 21:23:34
%S 1,2,3,1,3,2,1,4,2,2,2,1,1,2,3,1,2,1,3,2,3,1,3,3,4,1,1,2,1,2,1,5,1,4,
%T 1,1,2,2,1,1,3,2,1,4,2,2,2,1,1,1,4,1,1,1,1,3,2,3,1,5,1,4,2,2,1,1,1,1,
%U 2,3,1,2,1,3,4,1,1,3,3,4,1,1,2,3,1,5
%N Difference sequence of A325427.
%C See A325417 for a guide to related sequences. Conjecture: every term is in {1,2,3,4,5,6}.
%H Clark Kimberling, <a href="/A325520/b325520.txt">Table of n, a(n) for n = 1..10000</a>
%t a = {1}; Do[AppendTo[a, NestWhile[# + 1 &, Last[a] + 1, Apply[Or,
%t Map[MemberQ[a, #] &, Select[Flatten[{(# - 1)/2,
%t If[Mod[#, 3] == 0, (2 #)/3, 0] + If[Mod[#, 3] == 1, 1/3 (1 + 2 #), 0]}],
%t IntegerQ || # == 0]]] &]], {200}]; a ; (* A325427 *)
%t c = Complement[Range[Last[a]], a] ; (* A325428 *)
%t Differences[a] (* A325520 *)
%t Differences[c] (* A325521 *)
%t (* _Peter J. C. Moses_, Apr 23 2019 *)
%Y Cf. A325417, A325427, A325521.
%K nonn,easy
%O 1,2
%A _Clark Kimberling_, May 06 2019