title: Export DataTables to PDF is repeating the header
body: <p>I am using the function to export PDF from jquery DataTables. It works but it repeats the header like the image below:</p>
  
  <p><a href="https://i.stack.imgur.com/FDiuH.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/FDiuH.jpg" alt="enter image description here"></a></p>
  
  <p>Does anyone know of any way to export not repeating the header?</p>
  
  <pre class="lang-js prettyprint-override"><code>$("#table").DataTable({
      buttons: [
        {
        text: '&lt;i class="fas fa-file-pdf"&gt;&lt;/i&gt; PDF',
        extend: 'pdf',
        className: 'btn btn-danger',
        orientation: 'landscape',
        title: 'My table to PDF',
        pageSize: 'A3',
            exportOptions: {
              columns: [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 ]
          }
        }
    ],  
    responsive    : true,
    paging        : true,
    searching     : true
  });   
  </code></pre>