17. (6 points) Gymnasts are arranged in a square formation with the same number of people in each row and column. The outermost ring of each square formation has 16 people. If four such square formations can be combined to form a larger square formation, then the outermost ring of the larger square formation has $\qquad$ people.
【Analysis】Since the four vertices are shared by adjacent two sides, the number of people on each side is: $16 \div 4+1$ $=5$ (people), so each square has $5 \times 5=25$ (people), and four such squares can form a larger square, with a total of $25 \times 4=100$ (people). Since $100=10 \times 10$, there are 10 people in each row, and the number of people in the outermost circle is $10 \times 4-4=36$ (people). According to this, the answer is:

【Solution】
$$
16 \div 4+1=5 \text{ (people) }
$$
$$
\begin{array}{l}
5 \times 5=25 \text{ (people) } \\
25 \times 4=100 \text{ (people) } \\
10 \times 4-4=36 \text{ (people) }
\end{array}
$$

Answer: The outermost circle of the large square has 36 people.
The answer is: 36.