Question 861158
To try to find the pattern, look at the differences between consecutive numbers.
<table border="1" style="width:300px">
<tr>
  <td>Number</td>
  <td>Distance from the next</td>
</tr>
<tr>
  <td>3</td>
  <td>6</td>	
</tr>
<tr>
  <td>9</td>
  <td>-4</td>
</tr>
<tr>
  <td>5</td>
  <td>10</td>
</tr>
<tr>
  <td>15</td>
  <td>-4</td>
</tr>
<tr>
  <td>11</td>
  <td>33</td>
</tr>
<tr>
  <td>33</td>
  <td>-4</td>
</tr>
<tr>
  <td>29</td>
  <td></td>
</tr>
</table>
 
As you can see, every other number is four less than the one before it. However, the other numbers don't seem to follow an additive pattern. So, let's try division for every other number.
 
<table border="1" style="width:300px">
<tr>
  <td>Number</td>
  <td>Times to the next number</td>
</tr>
<tr>
  <td>3</td>
  <td>3</td>
</tr>
<tr>
  <td>5</td>
  <td>3</td>
</tr>
<tr>
  <td>11</td>
  <td>3</td>
</tr>
</table>
 
As you can see, for the other numbers, you multiply by three.
And so your pattern is 3 (*3) 9 (-4) 5 (*3) 15 (-4) 11 (*3) 33 (-4) 29.
Continue with 29 * 3, which is 87, and subtract 4 from that to get 83.
 
Your next numbers are 87 and 83