6. The following is a mathematical model of a pastry chef's work process:

As shown in Figure 2, on the number line, take the line segment corresponding to the closed interval $[0,4]$, fold it in half (the point corresponding to coordinate 4 overlaps with the origin), and then uniformly stretch it to a line segment of 4 units in length. This process is called one operation (for example, after the first operation, the original coordinates $1, 3$ become 2, the original coordinate 2 becomes 4, etc.). Therefore, the points on the original closed interval $[0,4]$ (excluding the two endpoints), after the $n$th $(n \geqslant 1)$ operation, the coordinates of the points that exactly overlap with 4 are $\qquad$
6. $\frac{j}{2^{n-2}}\left(j\right.$  is $\left[1,2^{n}\right]$ of all odd numbers $)$