  Fusion enhancement for neutron-rich isotopes of oxygen on carbon nuclei was
probed. To measure the fusion cross-section a $^{20}$O beam accelerated to
E$_{lab}$/A=2.7 MeV bombarded the active-target detector MuSIC@Indiana with a
fill gas of CH$_4$. Examination of the average fusion cross-section over the
interval 12 MeV $\leq$E$_{c.m.}$$\leq$ 17 MeV for $^{16-20}$O + $^{12}$C
reveals that while even isotopes of oxygen exhibit essentially the same
cross-section, the cross-section for odd isotopes can be either enhanced or
suppressed relative to the even A members of the isotopic chain. Theoretical
models fail to explain the observed experimental results.
