All Questions

The OEIS entry A121448 enumerates binary trees with $n$ edges and $k$ vertices with outdegree 1. Has anyone seen these trees? The o.g.f. for this entry, $G(x,t)$, is essentially a discriminant ...

Given a simple graph $G=(V,E)$, we can consider matchings, $M\subseteq E$, where $M$ is a matching iff no vertex is shared between different edges. The number of edges in $M$ is denoted $|M|$. The ...