<image>As shown in the figure, in the rectangle ABCD, AB=6. The first translation moves the rectangle ABCD 5 units to the right along the direction of AB, obtaining rectangle A_{1}B_{1}C_{1}D_{1}. The second translation moves the rectangle A_{1}B_{1}C_{1}D_{1} 5 units to the right along the direction of A_{1}B_{1}, obtaining rectangle A_{2}B_{2}C_{2}D_{2}. In general, the n-th translation moves the rectangle A_{n-1}B_{n-1}C_{n-1}D_{n-1} 5 units to the right along the direction of A_{n-1}B_{n-1}, obtaining rectangle A_{n}B_{n}C_{n}D_{n} (n > 2). The length of AB_{n} is _
