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A039501
Iterations of "n->n/2 if n even, n->3n-1 if n odd" (A001281) starting at these numbers reach 5.
4
5, 7, 9, 10, 13, 14, 18, 19, 20, 26, 27, 28, 35, 36, 38, 40, 47, 51, 52, 54, 56, 63, 70, 72, 75, 76, 80, 81, 89, 93, 94, 102, 104, 107, 108, 112, 119, 121, 125, 126, 133, 139, 140, 143, 144, 149, 150, 152, 159, 160, 161, 162, 167, 177, 178, 181, 186, 187, 188, 191
OFFSET
1,1
MATHEMATICA
it5Q[n_]:=Last[NestWhileList[If[EvenQ[#], #/2, 3#-1]&, n, #!=5&, 1, 100]]==5; Select[Range[200], it5Q] (* Harvey P. Dale, May 09 2012 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Christian G. Bower, Feb 15 1999
STATUS
approved