Answer
$a_1=3
\\a_2=7
\\a_3 = 11
\\a_4 = 15$
Work Step by Step
To find the first four terms of the given sequence, substitute 1, 2, 3, and 4 to $n$, respectively, then simplify.
$a_1 = 4(1) - 1 = 4 - 1 = 3
\\a_2 = 4(2) - 1 = 8 - 1 = 7
\\a_3 = 4(3) - 1 = 12 - 1 = 11
\\a_4 = 4(4) - 1 = 16 - 1 = 15$
