Answer
$a_{1}=4$
$a_{2}=28$
$a_{3}=196$
$a_{4}=1372$
$a_{5}=9604$
$a_{6}=67,228$
$a_{7}=470,596$
$a_{8}=3,294,172$
The sequence is geometric.
Work Step by Step
$a_{1}=4$
$a_{2}=7a_{1}=28$
$a_{3}=7a_{2}=196$
$a_{4}=7a_{3}=1372$
$a_{5}=7a_{4}=9604$
$a_{6}=7a_{5}=67,228$
$a_{7}=7a_{6}=470,596$
$a_{8}=7a_{7}=3,294,172$
The consecutive terms are such that $\displaystyle \frac{a_{n}}{a_{n-1}}=\frac{7a_{n-1}}{a_{n-1}}=7$
A common ratio exists, so the sequence is geometric.
