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A062059
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Numbers with 9 odd integers in their Collatz (or 3x+1) trajectory.
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4
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33, 65, 66, 67, 130, 131, 132, 133, 134, 260, 261, 262, 264, 266, 268, 269, 273, 289, 520, 522, 524, 525, 528, 529, 532, 533, 536, 538, 546, 547, 555, 571, 577, 578, 579, 583, 633, 635, 1040, 1044, 1045, 1048, 1050, 1056, 1058, 1059, 1064, 1066, 1072, 1076, 1077
(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)) = 9; A006667(a(n)) = 8.
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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..10000
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 33 is (33, 100, 50, 25, 76, 38, 19, 58, 29, 88, 44, 22, 11, 34, 17, 52, 26, 13, 40, 20, 10, 5, 16, 8, 4, 2, 1), which contains 9 odd integers.
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PROG
| (Haskell)
import Data.List (elemIndices)
a062059 n = a062059_list !! (n-1)
a062059_list = map (+ 1) $ elemIndices 9 a078719_list
-- Reinhard Zumkeller, Oct 08 2011
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CROSSREFS
| Cf. A062052-A062060.
Sequence in context: A053179 A183347 A116350 * A198592 A061560 A118618
Adjacent sequences: A062056 A062057 A062058 * A062060 A062061 A062062
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KEYWORD
| nonn
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AUTHOR
| David W. Wilson (davidwwilson(AT)comcast.net)
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