In the group of numbers 2, 5, 10, 17, 26, ___, 50, 65, how much should be filled on the horizontal line
在2、5、10、17、26、___、50、65这组数中，横线上应填多少
<gadget id="calculator">9 + 2</gadget>
<output>11</output>

<gadget id="calculator">26 + 11</gadget>
<output>37</output>

<result>37</result>