A222641 Number of iterations in Collatz (3x+1) trajectory of n to reach 1 from the highest term.

0, 1, 4, 2, 4, 4, 11, 3, 11, 4, 11, 4, 8, 11, 10, 4, 11, 11, 17, 7, 6, 11, 10, 10, 17, 8, 34, 11, 17, 10, 34, 5, 25, 11, 10, 11, 20, 17, 24, 8, 34, 6, 26, 11, 15, 10, 34, 11, 23, 17, 21, 11, 10, 34, 34, 19, 26, 17, 24, 10, 18, 34, 34, 6, 26, 25, 24, 14, 13, 10

Offset

1,3

Links

T. D. Noe, Table of n, a(n) for n = 1..10000

Formula

a(n) = A006577(n) - A220421(n);

Example

Collatz trajectory of 5 is 5, 16, 8, 4, 2, 1. Hence, a(5) = 4.

Mathematica

Collatz[n_] := NestWhileList[If[EvenQ[#], #/2, 3 # + 1] &, n, # > 1 &]; Table[c = Collatz[n]; Length[c] - Position[c, Max[c]][[1, 1]], {n, 100}] (* T. D. Noe, Feb 27 2013 *)

Crossrefs

Cf. A006577, A220421.

Sequence in context: A019921 A204617 A061469 * A368437 A258852 A021706

Adjacent sequences: A222638 A222639 A222640 * A222642 A222643 A222644

Keyword

nonn

Author

Jayanta Basu, Feb 27 2013

Status

approved