17. Given $h(0)=2$, for $n \geqslant 1$, $h(n)>0$, and
$$
h^{2}(n)-2 \cdot h^{2}(n-1)=1 \text {, }
$$

Find the general term formula for the sequence $\{h(n)\}_{n \geqslant 0}$.
17. $h(n)=\sqrt{5 \cdot 2^{n}-1}$.