Project Euler/239
From charlesreid1
Problem Statement
Twenty-two Foolish Primes
A set of disks numbered 1 through 100 are placed in a line in random order.
What is the probability that we have a partial derangement such that exactly 22 prime number discs are found away from their natural positions? (Any number of non-prime disks may also be found in or out of their natural positions.)
Give your answer rounded to 12 places behind the decimal point in the form 0.abcdefghijkl.
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