Observe the five formulas 1+3=4, 4+5=9, 9+7=16, 16+9=25, 25+11=36, find out the rules, and fill in 2000**2+how much=2001* *2.
观察1+3=4,4+5=9,9+7=16,16+9=25,25+11=36这五道算式，找出规律，然后填写2000**2+多少=2001**2．
<gadget id="calculator">2_001 ** 2</gadget>
<output>4_004_001</output>

<gadget id="calculator">2_000 ** 2</gadget>
<output>4_000_000</output>

<gadget id="calculator">4_004_001 - 4_000_000</gadget>
<output>4_001</output>

<result>4_001</result>