The conclusion of # 4341 shows that the generating function for the sequence $\{1, 1, 1, \cdots\}$ is $\frac{1}{1-x}$. Therefore, the answer is $\boxed{\frac{x^k}{1-x}}$

In general, if $f(x)$ is the generating function for the sequence $\{a_0, a_1, a_2, \cdots \}$, then $x^kf(x)$ is the generating function for the sequence $$\underbrace{0, 0, \cdots, 0}_{k}, a_0, a_1, a_2, \cdots$$