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A139391 Next odd term in Collatz trajectory with starting value n. 15
1, 1, 5, 1, 1, 3, 11, 1, 7, 5, 17, 3, 5, 7, 23, 1, 13, 9, 29, 5, 1, 11, 35, 3, 19, 13, 41, 7, 11, 15, 47, 1, 25, 17, 53, 9, 7, 19, 59, 5, 31, 21, 65, 11, 17, 23, 71, 3, 37, 25, 77, 13, 5, 27, 83, 7, 43, 29, 89, 15, 23, 31, 95, 1, 49, 33, 101, 17, 13, 35, 107, 9, 55, 37, 113, 19, 29 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

a(n) = A006370(n) iff n mod 4 = 2;

a(A016825(n))=A006370(A016825(n));

a(n) = A000265(A006370(n)).

a(A160967(n)) = 1. [From Reinhard Zumkeller, May 31 2009]

REFERENCES

Friedrich L. Bauer, 'Der (ungerade) Collatz-Baum', Informatik Spektrum 31 (Springer, April 2008).

LINKS

R. Zumkeller, Table of n, a(n) for n = 1..10000

Eric Weisstein's World of Mathematics, Collatz Problem

Index entries for sequences related to 3x+1 (or Collatz) problem

Wikipedia, Collatz conjecture [From Reinhard Zumkeller, May 31 2009]

FORMULA

a(n) = if A006370(n) is odd then A006370(n) else a(A006370(n)).

MATHEMATICA

a[n_]:=Select[NestWhileList[If[EvenQ[#], #/2, 3#+1] &, n, #>1 &], OddQ]; Prepend[Table[If[EvenQ[n], a[n][[1]], a[n][[2]]], {n, 2, 77}], 1] (* Jayanta Basu, May 27 2013 *)

CROSSREFS

Sequence in context: A179261 A154567 A260210 * A196612 A110635 A179773

Adjacent sequences:  A139388 A139389 A139390 * A139392 A139393 A139394

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Apr 17 2008

STATUS

approved

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Last modified September 21 15:13 EDT 2017. Contains 292300 sequences.