Alkanes with the First Three Maximal/Minimal Modified First Zagreb Connection Indices

The modified first Zagreb connection index ( ) is a molecular descriptor, which was initially appeared within a formula of the total electron energy of alternant hydrocarbons in 1972. In a recent paper [A. Ali, N. Trinajstić, A novel/old modification of the first Zagreb index, Mol. Inform . 37 (2018) 1800008], it was observed that the molecular descriptor correlates well with the entropy and acentric factor of octane isomers. In this article, the molecules with the first three maximal values as well as the first three minimal values are determined from the family of all alkanes with n carbon atoms, for . This extends the main results of the aforementioned paper.