As a modest start, I propose the below problem for a special set of partitions. Perhaps it is known.
Let $\lambda_n=(n,n-1,\dots,2,1)$ be the staircase partition and its corresponding Young diagram $Y_n$.
QUESTION. In how many different ways (denote this by $a_n$) can one tile $Y_n$ using monomers ($1\times1$ squares) and dimers ($1\times2$ or $2\times1$ rectangles)? Is there a determinant (Pfaffian) formulation of this enumeration, in Kasteleyn's style?