A sufficient condition for pancyclic graphs

A graph $G$ is called an $[s,t]$-graph if any induced subgraph of $G$ of order $s$ has size at least $t\mathrm{.}$ 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 Chvátal-Erdős condition. We also determine the triangle-free graphs among $[p+2,p]$-graphs for a general $p\mathrm{.}$