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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
J. C. Lagarias, The 3x+1 problem and its generalizations, Amer. Math. Monthly, 92 (1985), 3-23.
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
KEYWORD
nonn
AUTHOR
EXTENSIONS
More terms from Max Alekseyev, Oct 14 2012
STATUS
approved

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Last modified March 19 09:40 EDT 2024. Contains 370981 sequences. (Running on oeis4.)