Answer
$ a_1=4,a_2=11, a_3=25; a_4=53$
Work Step by Step
The general formula to find the nth term of a Geometric sequence is given as: $ a_{n}=a_1r^{n-1}$
In order to calculate the General formula of a Geometric sequence we will multiply the first term $ a_1$ by the product of the common ratio with itself one unit less then a Geometric sequence.
In order to calculate the first $4$ terms of the sequence we will have to plug $ n=1,2,3,4$ into the given equation; by doing so we get a recursive equation and we continue this to get the higher order terms.
So, we get $ a_1=4,a_2=11, a_3=25; a_4=53$
