Szeged index of TUC4C8(R) nanotubes

Let G be a graph. If (i, j) is an edge between vertices i and i of G and N(i) denote the number of vertices of G lying closer to vertex i than to j and N(j) denote the number of vertices of G lying closer to vertex j than to i, the Szeged index of G is defined as Sz(G) = Sigma((i,j)) N(i)N(j), where (i,j) go over all edges of G. In this paper we derive an exact expression for Szeged index of TUC4C8(R) nanotubes.