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A185455 Trajectory of 7 under repeated application of the map in A185452. 4
7, 18, 9, 23, 58, 29, 73, 183, 458, 229, 573, 1433, 3583, 8958, 4479, 11198, 5599, 13998, 6999, 17498, 8749, 21873, 54683, 136708, 68354, 34177, 85443, 213608, 106804, 53402, 26701, 66753, 166883, 417208, 208604, 104302, 52151, 130378, 65189, 162973, 407433, 1018583, 2546458, 1273229, 3183073, 7957683, 19894208, 9947104 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

It is conjectured that this trajectory is unbounded, but this is an open problem.

REFERENCES

J. C. Lagarias, ed., The Ultimate Challenge: The 3x+1 Problem, Amer. Math. Soc., 2010; see page 89.

LINKS

Rémy Sigrist, Table of n, a(n) for n = 1..10000

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

MAPLE

f:=n->if n mod 2 = 0 then n/2 else (5*n+1)/2; fi;

T:=proc(n, M) global f; local t1, i; t1:=[n];

for i from 1 to M-1 do t1:=[op(t1), f(t1[nops(t1)])]; od: t1; end;

T(7, 120);

CROSSREFS

Cf. A185452, A185453, A185454.

Sequence in context: A113613 A070415 A034083 * A103570 A223247 A091832

Adjacent sequences:  A185452 A185453 A185454 * A185456 A185457 A185458

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Feb 04 2011

STATUS

approved

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Last modified January 20 20:51 EST 2022. Contains 350472 sequences. (Running on oeis4.)