  Binary sequences with minimal autocorrelations have applications in
communication engineering, mathematics and computer science. In statistical
physics they appear as groundstates of the Bernasconi model. Finding these
sequences is a notoriously hard problem, that so far can be solved only by
exhaustive search. We review recent algorithms and present a new algorithm that
finds optimal sequences of length $N$ in time $\Theta(N\,1.73^N)$. We computed
all optimal sequences for $N\leq 66$ and all optimal skewsymmetric sequences
for $N\leq 119$.
