OFFSET
1,1
COMMENTS
n=4, 1+2^n = 17, list = {17, 52, 26, 13, 40, 20, 10, 5, 16, 8, 4, 2, 1}, so a(4) = 13.
LINKS
T. D. Noe, Table of n, a(n) for n = 1..10000
FORMULA
a(n) = A008908(2^n+1).
MATHEMATICA
Collatz[n_] := NestWhileList[If[EvenQ[#], #/2, 3 # + 1] &, n, # > 1 &]; Table[Length[Collatz[2^n + 1]], {n, 100}] (* T. D. Noe, Jan 17 2013 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Sep 26 2002
STATUS
approved