title: Given Prime Number N, Compute the Next Prime?
body: <p>A coworker just told me that the C# Dictionary collection resizes by prime numbers for arcane reasons relating to hashing. And my immediate question was, "how does it know what the next prime is? do they story a giant table or compute on the fly? that's a scary non-deterministic runtime on an insert causing a resize"</p>
  
  <p>So my question is, given N, which is a prime number, what is the most efficient way to compute the next prime number?</p>