Erdős–Gyárfás power-of-two cycles problem
Show that every finite graph with minimum degree at least 3 contains a cycle whose length is a power of two (2^k with k ≥ 2).
References
While the question remains open, it was shown that the claim was true if the minimum degree of $G$ was sufficiently large; in fact in that case there is some large integer $\ell$ such that for every even integer $m\in [(\log\ell)8,\ell]$, $G$ contains a cycle of length $m$.
— Mathematical exploration and discovery at scale
(2511.02864 - Georgiev et al., 3 Nov 2025) in Subsection “Erdős–Gyárfás conjecture” (Section 4.28)