<image>As shown in the figure, there is a spiral diagram. The width of the spiral channel and the length of OB are both 1. The spiral intersects with the ray OA at points A_{1}, A_{2}, A_{3},…. If the spiral from point O to point A_{1} is the first loop (length is 7), from point A_{1} to point A_{2} is the second loop, and so on, then the length of the 11th loop is ____.
