In the crossnumber puzzle below, two cells have already been filled in with digits: a 7 and a 3. The empty squares represent one digit each and the black squares separate the numbers..

• When filled in, the horizontal and vertical sequences of digits will represent eleven 2- or 3-digit prime numbers.
• No digit appears more than once in any given row, column or either of the long diagonals.
• No even digit appears more than once anywhere.

<font size=+2> <center>

  7 ■ ■ ■ □
  □ □ ■ □ □
  ■ 3 □ □ ■
  □ □ ■ □ □
  □ ■ ■ ■ □

<center> <font>

There are no leading zeros in any of the primes. <hr> From Enigma No. 1755, "Sudoprime II", by Peter Chamberlain, New Scientist, 29 June 2013, page 30.

<table border="0" cellpadding="0" cellspacing="0" width="70" style="border-collapse:
 collapse;width:55pt">
 <colgroup><col width="14" span="5" style="mso-width-source:userset;mso-width-alt:512;
 width:11pt">
 </colgroup><tbody><tr height="20" style="height:15.0pt">
  <td height="20" class="xl65" width="14" style="height:15.0pt;width:11pt">7</td>
  <td class="xl65" width="14" style="width:11pt">x</td>
  <td class="xl65" width="14" style="width:11pt">x</td>
  <td class="xl65" width="14" style="width:11pt">x</td>
  <td class="xl65" width="14" style="width:11pt">3</td>
 </tr>
 <tr height="20" style="height:15.0pt">
  <td height="20" class="xl65" style="height:15.0pt">3</td>
  <td class="xl65">1</td>
  <td class="xl65">x</td>
  <td class="xl65">6</td>
  <td class="xl65">7</td>
 </tr>
 <tr height="20" style="height:15.0pt">
  <td height="20" class="xl65" style="height:15.0pt">x</td>
  <td class="xl65">3</td>
  <td class="xl65">0</td>
  <td class="xl65">7</td>
  <td class="xl65">x</td>
 </tr>
 <tr height="20" style="height:15.0pt">
  <td height="20" class="xl65" style="height:15.0pt">4</td>
  <td class="xl65">7</td>
  <td class="xl65">x</td>
  <td class="xl65">3</td>
  <td class="xl65">1</td>
 </tr>
 <tr height="20" style="height:15.0pt">
  <td height="20" class="xl65" style="height:15.0pt">1</td>
  <td class="xl65">x</td>
  <td class="xl65">x</td>
  <td class="xl65">x</td>
  <td class="xl65">9</td>
 </tr></tbody></table>

Posted by sum on 2013-10-12 22:25:26