A quaternary Legendre pair of length $\ell$ is a pair of sequences over $\{\pm 1, \pm \mathrm{i}\}$ whose periodic autocorrelations sum to $-2$ at every nonzero shift. We give a quaternary Legendre pair of length $64$. To the best of our knowledge, this is the first reported construction at this length.

翻译：暂无翻译