A series of numbers arranged according to the law: 1, 2, 4, 7, 11, 16, ..., then what is the 1347th number in this series of numbers.
按规律排列的一串数：1，2，4，7，11，16，…，那么这串数的第1347个数是多少．
<gadget id="calculator">1 + 1_346</gadget>
<output>1_347</output>

<gadget id="calculator">1_346 / 2</gadget>
<output>673</output>

<gadget id="calculator">1_347 * 673</gadget>
<output>906_531</output>

<gadget id="calculator">1 + 906_531</gadget>
<output>906_532</output>

<result>906_532</result>