A sequence: 1, 2, 4, 7, 11, 16..., what is the 10th number in this sequence.
一数列：1、2、4、7、11、16…，这数列的第10个数是多少．
<gadget id="calculator">7 - 1</gadget>
<output>6</output>

<gadget id="calculator">16 + 6</gadget>
<output>22</output>

<gadget id="calculator">8 - 1</gadget>
<output>7</output>

<gadget id="calculator">22 + 7</gadget>
<output>29</output>

<gadget id="calculator">9 - 1</gadget>
<output>8</output>

<gadget id="calculator">29 + 8</gadget>
<output>37</output>

<gadget id="calculator">10 - 1</gadget>
<output>9</output>

<gadget id="calculator">37 + 9</gadget>
<output>46</output>

<result>46</result>