OFFSET
1,2
COMMENTS
The sequence necessarily starts with 1. The next 2 terms are determined as follows: because a(1) = 1, the number 2 is disallowed, so that a(2) = 3, whence the numbers 4 and 6 are disallowed, and a(3) = 5. See A325417 for a guide to related sequences.
LINKS
Clark Kimberling, Table of n, a(n) for n = 1..10000
MATHEMATICA
a = {1}; Do[AppendTo[a, NestWhile[# + 1 &, Last[a] + 1, Apply[Or,
Map[MemberQ[a, #] &, Select[Flatten[{#/2,
If[Mod[#, 3] == 0, (2 #)/3, 0] + If[Mod[#, 3] == 1, 1/3 (1 + 2 #), 0]}],
IntegerQ || # == 0]]] &]], {150}]; a (* A325425 *)
Complement[Range[Last[a]], a]; (* A325426 *)
(* Peter J. C. Moses, Apr 25 2019 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Apr 27 2019
STATUS
approved