a)
Let
$$P(x)=\sum_{n=0}^{\infty} p_nx^n=1+x+2x^2+3x^3+5x^4+7x^5+11x^6+\cdots$$
be the partition generating function, and let $Q(x)=\sum_{n=0}^{\infty} q_nx^n$, where $q_n$ is the number of partitions of $n$ containing no $1$s.
Then $\displaystyle\frac{Q(x)}{P(x)}$ is a polynomial. What polynomial is it?
b)
Let $P(x)$ be the partition generating function, and let $R(x)=\sum_{n=0}^{\infty} r_nx^n$, where $r_n$ is the number of partitions of $n$ containing no $1$s or $2$s.
Then $\displaystyle \frac{R(x)}{P(x)}$ is a polynomial. What polynomial is it? (Put answer in expanded form)
How can I start this problem?
Best Answer
Hint: Try to understand why $$P(x)=\frac{1}{\prod_{n=1}^{\infty}\left(1-x^n\right)},$$ and what are the corresponding expressions for $Q(x)$ and $R(x)$.
Spoiler: