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A143812
Maximal number of halving and tripling steps to reach 1 in '3x+1' problem for range (1, ..., n).
0
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
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
Sequence in context: A183393 A284781 A289841 * A245508 A193639 A154481
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