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A066756
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Smallest number that requires n^3 steps to reach 1 in its Collatz trajectory (counting x/2 and 3x+1 steps).
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0
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1, 2, 6, 65, 673, 342, 2919, 129991, 1590511, 301695657, 1412987847
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| a(11) > 7*10^11. - Donovan Johnson
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REFERENCES
| R. K. Guy, Problem E16, Unsolved Problems in Number Theory, 2nd edition, Springer-Verlag, NY pp. 215-218
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LINKS
| Index entries for sequences related to 3x+1 (or Collatz) problem
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FORMULA
| Collatz: n = n/d if n even else n = 3*n+1, count the steps until n=1
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EXAMPLE
| sequence(2) = 6 since trajectory of 6 is (6,3,10,5,16,8,4,2,1), 8 steps = 2^3
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CROSSREFS
| Cf. A006577, A066773.
Sequence in context: A052522 A193609 A061999 * A070872 A055685 A082619
Adjacent sequences: A066753 A066754 A066755 * A066757 A066758 A066759
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KEYWORD
| more,nonn
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AUTHOR
| Randall L. Rathbun, Jan 18 2002
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EXTENSIONS
| More terms from Larry Reeves (larryr(AT)acm.org), Apr 12 2002
a(10) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Nov 13 2010
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