Answer
$a_1=7
\\a_2=13
\\a_3=31
\\a_4=85
\\a_5=247$
The sequence has no common ratio so it is not geometric.
Work Step by Step
To find the first five terms, substitute 1, 2, 3, 4, and 5 to the given formula to obtain:
$a_1 = 4+3^1=4+3=7
\\a_2 = 4+3^2=4+19=13
\\a_3 = 4+3^3=4+27=31
\\a_4=4+3^4 = 4+81=85
\\a_5=4+3^5 = 4+243 = 247$
RECALL:
A sequence is geometric if there is a common ratio among consecutive terms.
The consecutive terms have no common ratio therefore the sequence is not geometric.