The formula for a general term in a geometric sequence is given by
![a_n=a_1r^(n-1)](https://img.qammunity.org/2023/formulas/mathematics/college/3vairmyfpr17lk1iiy49tgudwjvjyhpikm.png)
The first term of our sequence is 16, then, our geometric sequence would be
![a_n=16r^(n-1)](https://img.qammunity.org/2023/formulas/mathematics/college/4lj077wwjw0u0h08h46zwuh83o0bfzimk0.png)
Using the following terms, there's no r that fits for all terms, therefore, this sequence is not geometric.
The general term in a arithmetic sequence is
![a_n=a_1+(n-1)d](https://img.qammunity.org/2023/formulas/mathematics/high-school/8ad7drcg9vuq9sminhqfaw7j3r5r4u1ij9.png)
Where d is the common ratio.
Again, the first term is 16. Using the second term, we can find the value for d.
![\begin{gathered} a_n=16+(n-1)d \\ a_2=(15)/(2)\Rightarrow d=(15)/(2)-16=-(17)/(2) \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/1e60jju9i8s0uocnvsacu8x4qabd4e57hy.png)
This arithmetic sequence is
![a_n=16-(17)/(2)(n-1)](https://img.qammunity.org/2023/formulas/mathematics/college/epddbp6kmufwoefsneh1tsbo1xknb6m7ty.png)
If we evaluate bigger values for n to check with the other given terms, we have a match.
![\begin{gathered} a_3=16-(17)/(2)(3-1)=16-17=-1 \\ a_4=16-(17)/(2)(4-1)=(32)/(2)-(51)/(2)=-(19)/(2) \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/qoym0pqz2ky6iv6p0fppr3u2j1sgdeuftq.png)
Thus, this series converge because it is arithmetic.