+1786 A permutation of the numbers (1,2,3,\dots,n) is a rearrangement of the numbers in which each number appears exactly once. For example, (2,5,1,4,3)$ is a permutation of (1,2,3,4,5).
Let \pi = (x_1,x_2,x_3,\dots,x_n) be a permutation of the numbers (1,2,3,\dots,n). A fixed point of \pi is an integer k, 1 \le k \le n, such that x_k = k. For example, 4 is a fixed point of the permutation (2,5,1,4,3).
How many permutations of (1,2,3,4,5,6,7) have at least four fixed point?
