<p>Return the number of permutations of 1 to <code>n</code> so that prime numbers are at prime indices (1-indexed.)</p> <p><em>(Recall that an integer is prime if and only if it is greater than 1, and cannot be written as a product of two positive integers both smaller than it.)</em></p> <p>Since the answer may be large, return the answer <strong>modulo <code>10^9 + 7</code></strong>.</p> <p> </p> <p><strong>Example 1:</strong></p> <pre> <strong>Input:</strong> n = 5 <strong>Output:</strong> 12 <strong>Explanation:</strong> For example [1,2,5,4,3] is a valid permutation, but [5,2,3,4,1] is not because the prime number 5 is at index 1. </pre> <p><strong>Example 2:</strong></p> <pre> <strong>Input:</strong> n = 100 <strong>Output:</strong> 682289015 </pre> <p> </p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 <= n <= 100</code></li> </ul>