Symbols used in partitions

Question

What is the LaTeX code for the symbols for the set of all odd partition and the set of all distinct partitions? I need to use them for a chapter on Euler's theorem in a report about partition theory.

They are both on page 3 of this article on the last line of theorem 1.1: Chen, William Y. C.; Yee, Ae Ja; Zhu, Albert J. W., Euler’s partition theorem with upper bounds on multiplicities, Electron. J. Comb. 19, No. 3, Research Paper P41, 15 p. (2012).

Answer 1

using $\mathcal{D}$ and $\mathcal{O}$

\documentclass{article}
\begin{document}
    \[
        \sum_{\lambda \in \mathcal{D}} y^{l_a(\lambda)}q^{|\lambda|} = \sum_{\mu\in\mathcal{O}}y^{l(\mu)}q^{|\mu|}
\]
\end{document}