OFFSET
1,2
COMMENTS
A consequence of the Collatz conjecture is that, after a(5), this would be equivalent to the list of positive integers with Collatz trajectories that include the number 32.
LINKS
EXAMPLE
21 is a term because its Collatz trajectory, given in A033481, does not include 5.
MATHEMATICA
collatzTrajectory[n_] := NestWhileList[If[EvenQ[#], #/2, 3 # + 1] &, n, # > 1 &]; Select[Range[1000], Not[MemberQ[collatzTrajectory[#], 5]] &] (* Alonso del Arte, May 25 2019 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Nathan Bumber, May 14 2019
STATUS
approved