title: There is no Zero in Mathematics Digits Riddle
body: <p>This gives me:</p>
  <pre><code>?- X is 10^10//81-1.
  X = 123456789.
  </code></pre>
  <p>So the expression delivers a number with all non-zero<br />
  digits. Is there another formula that delivers all digits,<br />
  possibly permuted, where the formula itself has no zero in it?</p>
  <p>Can we find such a formula with Prolog or CLP(FD)?</p>