In the sequence 1, 4, 7, 10, 13..., what is the 1000th number from left to right?
在数列1、4、7、10、13…中，从左往右数第1000个数是多少．
<gadget id="calculator">1_000 - 1</gadget>
<output>999</output>

<gadget id="calculator">999 * 3</gadget>
<output>2_997</output>

<gadget id="calculator">1 + 2_997</gadget>
<output>2_998</output>

<result>2_998</result>