There is a column of numbers: 1, 2, 2, 3, 3, 3, 4, 4, 4, 4, ..., and each number n is written n times. When writing 20, how many times does the number "1" appear.
有一列数：1、2、2、3、3、3、4、4、4、4、…，每个数n都写了n次．当写到20的时候，数字"1"出现了多少次．
<gadget id="calculator">11 * 2</gadget>
<output>22</output>

<gadget id="calculator">1 + 10 + 22 + 12 + 13 + 14 + 15 + 16 + 17 + 18 + 19</gadget>
<output>157</output>

<result>157</result>