On the number of outer connected dominating sets of graphs
  Let $G=(V,E)$ be a simple graph. A set $S\subseteq V(G)$ is called an outer-connected dominating set (or ocd-set) of $G$, if $S$ is a dominating set of $G$ and either $S=V(G)$ or $V\backslash S$ is a connected graph. In this paper we introduce a polynomial which its coefficients are the number of ocd-sets of $G$. We obtain some properties of this polynomial and its coefficients. Also we compute this polynomial for some specific graphs. 
Saeid Alikhani, Mohammad H. Akhbari, C. Eslahchi, Roslan Hasni
math.CO