The fourth grade students of a certain school are arranged in a solid square. The number of people on the outermost layer is 60. How many students are there in this square.
某校四年级学生排成一个实心方阵，最外一层的人数为60人，这个方阵共有学生多少人．
<gadget id="calculator">60 / 4</gadget>
<output>15</output>

<gadget id="calculator">15 + 1</gadget>
<output>16</output>

<gadget id="calculator">16 * 16</gadget>
<output>256</output>

<result>256</result>