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A062056
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Numbers with 6 odd integers in their Collatz (or 3x+1) trajectory.
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3
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7, 14, 15, 28, 29, 30, 56, 58, 60, 61, 112, 116, 117, 120, 122, 224, 232, 234, 240, 241, 244, 245, 267, 448, 464, 468, 469, 480, 482, 483, 488, 490, 497, 534, 535, 537, 896, 928, 936, 938, 960, 964, 965, 966, 976, 980, 981, 985, 994, 995, 1068, 1069, 1070, 1073
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| The Collatz (or 3x+1) function is f(x) = x/2 if x is even, 3x+1 if x is odd.
The Collatz trajectory of n is obtained by applying f repeatedly to n until 1 is reached.
Sequence is 2-automatic.
A078719(a(n)) = 6; A006667(a(n)) = 5.
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REFERENCES
| J. Shallit and D. Wilson, The "3x+1" Problem and Finite Automata, Bulletin of the EATCS #46 (1992) pp. 182-185.
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LINKS
| Reinhard Zumkeller, Table of n, a(n) for n = 1..1000
J. Shallit and D. Wilson, The "3x+1" Problem and Finite Automata, Bulletin of the EATCS #46 (1992) pp. 182-185.
Eric Weisstein's World of Mathematics, CollatzProblem
Wikipedia, Collatz conjecture
Index entries for sequences related to 3x+1 (or Collatz) problem
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EXAMPLE
| The Collatz trajectory of 7 is (7, 22, 11, 34, 17, 52, 26, 13, 40, 20, 10, 5, 16, 8, 4, 2, 1), which contains 6 odd integers.
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PROG
| (Haskell)
import Data.List (elemIndices)
a062056 n = a062056_list !! (n-1)
a062056_list = map (+ 1) $ elemIndices 6 a078719_list
-- Reinhard Zumkeller, Oct 08 2011
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CROSSREFS
| Cf. A062052-A062060.
Sequence in context: A141164 A004781 A004759 * A173024 A115770 A086779
Adjacent sequences: A062053 A062054 A062055 * A062057 A062058 A062059
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KEYWORD
| nonn
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AUTHOR
| David W. Wilson (davidwwilson(AT)comcast.net)
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