Answer
$2\times1=2$
$2\times(1+3)=8$
$2\times(1+3+5)=18$
$2\times(1+3+5+7)=32$
Work Step by Step
This question only needs to be dealt with by mathematical calculations.
$2\times1=2$
$2\times(1+3)=2\times4=8$
$2\times(1+3+5)=2\times9=18$
$2\times(1+3+5+7)=2\times16=32$