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##### The Extremal Graph with the Largest Merrifield-Simmons Index of (n, n + 2)-graphs

**Authors:**
M. S. Haghighat,
A. Dolati,
M. Tabari,
E. Mohseni

**Abstract:**

The Merrifield-Simmons index of a graph G is defined as the total number of its independent sets. A (n, n + 2)-graph is a connected simple graph with n vertices and n + 2 edges. In this paper we characterize the (n, n+2)-graph with the largest Merrifield- Simmons index. We show that its Merrifield-Simmons index i.e. the upper bound of the Merrifield-Simmons index of the (n, n+2)-graphs is 9 × 2n-5 +1 for n ≥ 5.

**Keywords:**
Merrifield-Simmons index,
n+2)-graph

**Digital Object Identifier (DOI):**
doi.org/10.5281/zenodo.1083357

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