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A085817 Start at (2n+1)/4 and iterate the map x -> x*ceiling(x); sequence gives values of n for which the denominators in the orbit drop directly from 4 to 1, bypassing 2. 3
4, 6, 7, 9, 12, 13, 14, 15, 20, 21, 22, 23, 24, 30, 31, 36, 38, 39, 41, 44, 45, 46, 47, 52, 53, 54, 55, 56, 62, 63, 69, 70, 71, 73, 76, 77, 78, 79, 81, 86, 87, 88, 94, 95, 96, 97, 101, 102, 103, 105, 108, 109, 110, 111, 112, 118, 119, 120, 126, 127, 129, 132, 133, 134, 135, 137 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

No formula is known for these numbers.

LINKS

Table of n, a(n) for n=1..66.

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

CROSSREFS

Complement of A085833.

A073341 gives number of steps until reach an integer. Cf. A085785.

Sequence in context: A256792 A345665 A343177 * A177688 A190250 A047508

Adjacent sequences: A085814 A085815 A085816 * A085818 A085819 A085820

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Aug 16 2003

STATUS

approved

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Last modified March 21 16:20 EDT 2023. Contains 361408 sequences. (Running on oeis4.)