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A006513 Limit of the image of n after 2k iterates of `(3x+1)/2' map as k grows.
(Formerly M0189)
4
1, 2, 2, 1, 1, 1, 2, 2, 2, 2, 1, 2, 2, 1, 1, 1, 2, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 2, 2, 2, 2, 2, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 1, 2, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The map is x -> (3x+1)/2 for odd x, and x -> x/2 for even x.

REFERENCES

R. K. Guy, Unsolved Problems in Number Theory, E16.

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

LINKS

Table of n, a(n) for n=1..109.

J. C. Lagarias, The 3x+1 problem and its generalizations, Amer. Math. Monthly, 92 (1985), 3-23.

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

PROG

(PARI) f(n) = if (n%2, (3*n+1)/2, n/2); \\ A014682

a(n) = my(last = n); while (1, my(new = f(f(last))); if (new == last, return(new)); last = new; ); \\ Michel Marcus, Feb 03 2022

CROSSREFS

Cf. A014682.

Sequence in context: A324381 A331383 A201208 * A105224 A261627 A237112

Adjacent sequences:  A006510 A006511 A006512 * A006514 A006515 A006516

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Max Alekseyev, Oct 14 2012

STATUS

approved

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Last modified June 29 09:21 EDT 2022. Contains 354910 sequences. (Running on oeis4.)