OFFSET
1,3
COMMENTS
LINKS
T. D. Noe, Table of n, a(n) for n = 1..10000
MATHEMATICA
Collatz[n_] := NestWhileList[If[EvenQ[#], #/2, 3 # + 1] &, n, # > 1 &]; Table[c = Collatz[n]; co = Select[c, OddQ]; If[Length[co] == 1, 0, co[[-2]]], {n, 100}]
CROSSREFS
KEYWORD
nonn
AUTHOR
T. D. Noe, Feb 21 2014
STATUS
approved