A085833 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 go from 4 to 2, instead of dropping directly to 1.

2, 3, 5, 8, 10, 11, 16, 17, 18, 19, 25, 26, 27, 28, 29, 32, 33, 34, 35, 37, 40, 42, 43, 48, 49, 50, 51, 57, 58, 59, 60, 61, 64, 65, 66, 67, 68, 72, 74, 75, 80, 82, 83, 84, 85, 89, 90, 91, 92, 93, 98, 99, 100, 104, 106, 107, 113, 114, 115, 116, 117, 121, 122, 123, 124, 125, 128, 130

Offset: 1

Author

N. J. A. Sloane, Aug 16 2003

Keywords

• nonn

Comments

No formula is known for these numbers.

Links

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

Crossrefs

Complement of A085817.

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