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A213204
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Number of terms of the Collatz (3x+1) trajectory of n that are greater than or equal to n.
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1
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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, 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, 5, 7, 92, 94, 1, 6, 4, 7, 1, 3, 4, 88, 1, 98, 2, 8, 2, 4, 11, 14
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OFFSET
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1,3
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LINKS
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FORMULA
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EXAMPLE
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For n=3, the Collatz trajectory is 3, 10, 5, 16, 8, 4, 2, 1 and hence a(3)=6.
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MATHEMATICA
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Collatz[n_] := NestWhileList[If[EvenQ[#], #/2, 3 # + 1] &, n, # > 1 &]; Table[Length[Select[Collatz[n], # >= n &]], {n, 100}]
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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