Answer
$a_1=-2$
$a_2=1$
$a_3=4$
$a_4=7$
Work Step by Step
$a_1=-2$
$a_2=a_1+3=-2+3=1$
$a_3=a_2+3=1+3=4$
$a_4=a_3+3=4+3=7$
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