title: Is there an R function to get the number of permutations of n objects take k P(n,k)?
body: <p>..or do I have to give</p>
  
  <pre><code>P.nk &lt;- factorial(n) / factorial(n-k)
  </code></pre>
  
  <p>or</p>
  
  <pre><code>P.nk &lt;- choose(n,k) * factorial(k)
  </code></pre>
  
  <p>Thank you.</p>