The peddler sells (1/2) and half of all his watermelons to the first customer, and sells the remaining (1/2) and half to the second customer. In this way, he sells (1/2) of the remaining watermelons 2) Another half was sold to future customers. After selling to the 7th customer, it was just sold out. How many watermelons does the hawker have in total?
小贩把他所有西瓜的(1/2)又半个卖给第一位顾客，把余下的(1/2)又半个卖给第二位顾客，这样，他把所余西瓜的(1/2)又半个卖给以后各位顾客，卖给第7位顾客后，刚好卖完．小贩共有多少个西瓜？
<gadget id="calculator">0.5 * 2</gadget>
<output>1</output>

<gadget id="calculator">1 + 0.5</gadget>
<output>1.5</output>

<gadget id="calculator">1.5 * 2</gadget>
<output>3</output>

<gadget id="calculator">3 + 0.5</gadget>
<output>3.5</output>

<gadget id="calculator">3.5 * 2</gadget>
<output>7</output>

<gadget id="calculator">7 + 0.5</gadget>
<output>7.5</output>

<gadget id="calculator">7.5 * 2</gadget>
<output>15</output>

<gadget id="calculator">15 + 0.5</gadget>
<output>15.5</output>

<gadget id="calculator">15.5 * 2</gadget>
<output>31</output>

<gadget id="calculator">31 + 0.5</gadget>
<output>31.5</output>

<gadget id="calculator">31.5 * 2</gadget>
<output>63</output>

<gadget id="calculator">63 + 0.5</gadget>
<output>63.5</output>

<gadget id="calculator">63.5 * 2</gadget>
<output>127</output>

<result>127</result>