Simplify and Write Without Negative Exponents $\left(\frac{a^{n+1}}{a^{n^{2}+1}}\right) \div\left(\frac{a^{n-1}}{a^{n+1}}\right)^{n}$

Simplify and write without negative exponents: $\left(\frac{a^{n+1}}{a^{n^{2}+1}}\right) \div\left(\frac{a^{n-1}}{a^{n+1}}\right)^{n}$