On a conjecture of Gentner and Rautenbach

Gentner and Rautenbach conjectured that the size of a minimum zero forcing set in a connected graph on n vertices with maximum degree 3 is at most 13n+2. We disprove this conjecture by constructing a collection of connected graphs {Gn} with maximum degree 3 of arbitrarily large order having zero forcing number at least 49|V(Gn)|.