# My Tenth Problem

**Algebra**Level pending

Let \(n\in\mathbb{N}\) and \(f(0)=1\).

Simplify \(f\) for:

\(f(n)=k^{n}+\sum_{a=1}^{n}[k^{a-1}\times(k^{n-a}+\sum_{b=1}^{n-a}[k^{b-1}\times(k^{n-a-b}+\sum_{c=1}^{n-a-b}[k^{c-1}\times(k^{n-a-b-c}+\sum_{d=1}^{n-a-b-c}[... ...])])])]\)

for an arbitrary constant \(k\), where \(f\) is a function of a natural number or \(0\).