A sufficient condition for pancyclic graphs

Abstract

A graph $G$ is called an $[s,t]$-graph if any induced subgraph of $G$ of order $s$ has size at least $t.$ We prove that every $2$-connected $[4,2]$-graph of order at least $7$ is pancyclic. This strengthens existing results. There are $2$-connected $[4,2]$-graphs which do not satisfy the Chv\'{a}tal-Erd\H{o}s condition. We also determine the triangle-free graphs among $[p+2,p]$-graphs for a general $p.$