A216059 Smallest number not in Collatz trajectory starting at n.

2, 3, 6, 3, 3, 7, 3, 3, 3, 3, 3, 7, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 7, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 7, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3

Offset

1,1

Comments

a(n) <= 7; a(A007283(n)) = 7;

a(n) <> 4; a(n) <> 4; a(n) <> 6 for n > 3;

a(n) = A216022(n) + 1.

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..1000

Eric Weisstein's World of Mathematics, Collatz Problem

Wikipedia, Collatz conjecture

Index entries for sequences related to 3x+1 (or Collatz) problem

Mathematica

scoll[n_]:=Sort[NestWhileList[If[EvenQ[#], #/2, 3#+1] &, n, #>1 &]]; Join[{2, 3}, Table[i=1; While[scoll[n][[i]]==i, i++]; i, {n, 3, 86}]] (* Jayanta Basu, May 27 2013 *)

Prog

(Haskell)
import Data.List ((\\))
a216059  n = head $ enumFromTo 1 (maximum ts + 1) \\ ts
   where ts = a070165_row n

Crossrefs

Cf. A006370, A070165.

Sequence in context: A322229 A245886 A224504 * A261814 A240965 A084228

Adjacent sequences: A216056 A216057 A216058 * A216060 A216061 A216062

Keyword

nonn

Author

Reinhard Zumkeller, Sep 01 2012

Status

approved