Computing Eccentric Version of Second Zagreb Index of Polycyclic Aromatic Hydrocarbons (PAHk)

A Recently, Ghorbani et. al. introduced the eccentric versions of first and second Zagreb indices called third and fourth Zagreb indices defined asM₃ (G) = Σ_uv∊E(G) (ε (u) + ε (ν)) and M₄ (G) = Σ_ν∊V(G)ε (ν)², respectively, where ε (ν)is the eccentricity of the vertex ν. In this paper, we compute the closed formula for third Zagreb index of Polycyclic Aromatic Hydrocarbons (PAH_k).