Packebusch, T.,Mertens, S.

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 O(N 1.73(N)). We computed all optimal sequences for N <= 66 and all optimal skewsymmetric sequences for N <= 119.