Answer
$a_1=0$
$a_2=3$
$a_3=8$
$a_4=15$
$a_{100}=9999$
Work Step by Step
We are given:
$a_{n}=n^{2}-1$
We evaluate:
$a_1=(1)^{2}-1=1-1=0$
$a_2=(2)^{2}-1=4-1=3$
$a_3=(3)^{2}-1=9-1=8$
$a_4=(4)^{2}-1=16-1=15$
$a_{100}=(100)^{2}-1=9999$