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Number of terms of the Collatz (3x+1) trajectory of n that are greater than or equal to n.
1

%I #10 Mar 01 2013 15:04:32

%S 1,1,6,1,3,4,13,1,14,2,9,2,4,9,12,1,5,8,11,1,3,5,8,1,11,2,103,4,6,9,

%T 98,1,11,3,6,3,5,6,18,1,98,2,11,2,4,6,93,1,6,5,8,1,3,96,99,1,10,2,12,

%U 5,7,92,94,1,6,4,7,1,3,4,88,1,98,2,8,2,4,11,14

%N Number of terms of the Collatz (3x+1) trajectory of n that are greater than or equal to n.

%H T. D. Noe, <a href="/A213204/b213204.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = A222597(n) - 1.

%e For n=3, the Collatz trajectory is 3, 10, 5, 16, 8, 4, 2, 1 and hence a(3)=6.

%t Collatz[n_] := NestWhileList[If[EvenQ[#], #/2, 3 # + 1] &, n, # > 1 &]; Table[Length[Select[Collatz[n], # >= n &]], {n, 100}]

%Y Cf. A076228, A222597.

%K nonn

%O 1,3

%A _Jayanta Basu_, Mar 01 2013