There are 1 gram, 2 gram, 4 gram, 8 gram, and 16 gram weights. When weighing things, the weights can only be placed on one side of the balance. How many different weights can be weighed with these weights?
现有1克、2克、4克、8克、16克的砝码各一个，称东西时，砝码只能放在天平的一边，用这些砝码可以称出多少种不同的重量．
<gadget id="calculator">1 + 2 + 4 + 8 + 16</gadget>
<output>31</output>

<result>31</result>