A143812 Maximal number of halving and tripling steps to reach 1 in '3x+1' problem for range (1, ..., n).

1, 2, 8, 8, 8, 9, 17, 17, 20, 20, 20, 20, 20, 20, 20, 20, 20, 21, 21, 21, 21, 21, 21, 21, 24, 24, 112, 112, 112, 112, 112, 112, 112, 112, 112, 112, 112, 112, 112, 112, 112, 112, 112, 112, 112, 112, 112, 112, 112, 112, 112, 112, 112, 113, 113, 113, 113, 113

Offset

1,2

Links

Table of n, a(n) for n=1..58.

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

Mathematica

nst[n_]:=Length[NestWhileList[If[EvenQ[#], #/2, 3#+1]&, n, #>1&]]; nn=60; With[ {stps= Array[nst, nn]}, Table[Max[Take[stps, n]], {n, nn}]]  (* Harvey P. Dale, Apr 17 2014 *)

Crossrefs

Cf. A006877, A033492.

Sequence in context: A183393 A284781 A289841 * A245508 A193639 A154481

Adjacent sequences: A143809 A143810 A143811 * A143813 A143814 A143815

Keyword

nonn

Author

Benjamin Frost (benjamin.frost(AT)students.adelaide.edu.au), Sep 02 2008

Extensions

Corrected and extended by Harvey P. Dale, Apr 17 2014

Status

approved