Suppose we have an undirected graph with integer valued nodes where node $i$ is connected to$0<|i-j|\le 2$ implies nodes $i+1$$i$ and $i+2$$j$ are connected. Let $c_n$ be the number of self-avoiding walks on this graph of length $n$ starting at origin. Define the connective constant as
$$\mu = \lim_{n\to \infty} c_n^{\frac{1}{n}}$$
What is known about $\mu$? This quantity seems to be related to the transition temperature of an Ising model on such graph, has such model been studied?