I have a question with a problem from the book "An Introduction to The Theory of Numbers" by Niven (5th edition). This question is for anyone who has the book. In Chapter $10$ section $\S 3$ Formal Power Series, in exercise $1$, it mentions $p'(n)$ at the end of the problem. I can't seem to find any reference as to what that means in the book. If anyone can shed some light on this problem I am having I would be grateful. I also check the list of errors posted on previous and current editions for this book and haven't found anything regarding this. Also, before the book begins, it has a list of symbols introduced in the book along with the page number, but I do not see the symbol $p'(n)$ in there. Unless the symbol $p'(n)$ is used for the derivative for $p(n)$.
Thanks!
EDIT: Exercise $1$: Show that the infinite product
$(1+x_1)(1+x_1x_2)(1+x_1x_2x_3)\cdots = 1 + \sum x_1^{a_1}x_2^{a_2}\cdots x_k^{a_k}$
where $a_i - a_{i+1}$ is $0$ or $1$, and $a_k = 1$. Count the number of terms in the expansion that are of degree $n$. Set $x_1 = x_2 = x_3 = \cdots = x$ to show that $(1+x)(1+x^2)(1+x^3)\cdots$ is the generating function for $p'(n)$ of Problem $1, \S 10.2$.
EDIT: I had initially said $\S 10.4$ but I had made a mistake. It is actually $\S 10.3$.