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A085785 Start at (2n+1)/4 and iterate the map x -> x*ceiling(x); sequence gives number of steps for denominator to drop to 1 or 2; or -1 if this never happens. 4
1, 1, 3, 7, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 6, 3, 1, 1, 4, 3, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 3, 3, 1, 1, 5, 3, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 3, 4, 1, 1, 3, 5, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 6, 7, 1, 1, 3, 5, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 5, 3, 1, 1, 5, 3, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 3, 3, 1, 1, 8, 3, 1, 1, 2, 2, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,3

COMMENTS

We conjecture that the denominator always does drop.

LINKS

Table of n, a(n) for n=2..106.

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

CROSSREFS

A073341 gives number of steps until reach an integer. Cf. A085817, A085833.

Sequence in context: A074051 A048292 A072450 * A200235 A127929 A228147

Adjacent sequences:  A085782 A085783 A085784 * A085786 A085787 A085788

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Aug 16 2003

STATUS

approved

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Last modified October 19 10:22 EDT 2018. Contains 316350 sequences. (Running on oeis4.)