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A087704 Number of steps for iteration of map x -> (5/3)*floor(x) to reach an integer > n when started at n, or -1 if no such integer is ever reached. 2
2, 1, 2, 4, 1, 3, 3, 1, 9, 2, 1, 2, 4, 1, 8, 5, 1, 3, 2, 1, 2, 3, 1, 9, 7, 1, 4, 2, 1, 2, 5, 1, 3, 3, 1, 4, 2, 1, 2, 8, 1, 6, 4, 1, 3, 2, 1, 2, 3, 1, 5, 4, 1, 6, 2, 1, 2, 7, 1, 3, 3, 1, 6, 2, 1, 2, 7, 1, 4, 5, 1, 3, 2, 1, 2, 3, 1, 4, 7, 1, 10, 2, 1, 2, 4, 1, 3, 3, 1, 5, 2, 1, 2, 4, 1, 8, 6, 1, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

COMMENTS

It is conjectured that an integer is always reached.

LINKS

Table of n, a(n) for n=2..100.

J. C. Lagarias and N. J. A. Sloane, Approximate squaring (pdf, ps), Experimental Math., 13 (2004), 113-128.

MAPLE

f2 := proc(x, y) x*floor(y); end; r := 5/3; h := proc(x) local n, y; global r; y := f2(r, x); for n from 1 to 20 do if whattype(y) = 'integer' then RETURN([x, n, y]); else y := f2(r, y); fi; od: RETURN(['NULL', 'NULL', 'NULL']); end; [seq(h(n)[2], n=2..60)];

CROSSREFS

Cf. A087705, A087706, A087707.

Sequence in context: A110162 A199087 A306913 * A165092 A306915 A270743

Adjacent sequences:  A087701 A087702 A087703 * A087705 A087706 A087707

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Sep 29 2003

STATUS

approved

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Last modified September 22 05:47 EDT 2019. Contains 327287 sequences. (Running on oeis4.)