Answer
$0$.
Work Step by Step
We have
$$
\lim _{n \rightarrow \infty} a_n=\lim _{n \rightarrow \infty}\frac{10^n}{n!}=0.
$$
Since we know that for all $n\gt \gt 10$, $n!$ is getting bigger faster than $10^n$. Hence, $a_n$ converges to $0$.