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.

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