A325494 - OEIS

%I #8 May 06 2019 08:48:29

%S 1,2,3,1,2,1,2,1,2,2,1,1,2,3,1,2,3,1,2,1,1,2,2,3,1,2,1,2,1,2,3,1,2,1,

%T 2,1,2,3,1,2,2,2,2,3,1,2,1,2,1,2,2,1,1,2,3,1,2,3,1,2,1,2,1,2,3,1,2,3,

%U 1,2,2,1,1,2,1,2,1,2,3,1,2,1,1,2,2,3

%N Difference sequence of A325419.

%C See A325417 for a guide to related sequences. Conjecture: every term is in {1,2,3}.

%H Clark Kimberling, <a href="/A325494/b325494.txt">Table of n, a(n) for n = 1..10000</a>

%e A325419 is given by A(n) = least number not 3*A(m) or 2*A(m)+1 for any m < n, so that A = (1,2,4,7,8,10,11,...), with differences (1,2,3,1,2,1,...).

%t a = {1}; Do[AppendTo[a, NestWhile[# + 1 &, Last[a] + 1,

%t Apply[Or, Map[MemberQ[a, #] &, Select[Flatten[{#/3, (# - 1)/2}],

%t IntegerQ]]] &]], {2000}]; a ;       (* A325419 *)

%t c = Complement[Range[Last[a]], a] ; (* A325420 *)

%t Differences[a]  (* A325494 *)

%t Differences[c]  (* A325495 *)

%t (* _Peter J. C. Moses_, Apr 23 2019 *)

%Y Cf. A325417, A325495.

%K nonn,easy

%O 1,2

%A _Clark Kimberling_, May 05 2019