From the sixteen natural numbers 1, 2, 3, 4, ..., 15, 16, randomly select n numbers, among which there must be two numbers: one is three times the other, then what is the smallest n.
从1，2，3，4，…，15，16这十六个自然数中，任取出n个数，其中必有这样的两个数：一个是另一个的3倍，则n最小是多少．
<gadget id="calculator">12 + 1</gadget>
<output>13</output>

<result>13</result>