Find the law of the following sequence of numbers, and fill in the appropriate number in the horizontal line according to the law: 2, 9, 16, 23, how many, 37.
找出下列数列的规律，并按其规律在横线内填上合适的数：2，9，16，23，多少，37．
<gadget id="calculator">23 + 7</gadget>
<output>30</output>

<result>30</result>