A combinatorial proof of the non-vanishing of Hankel determinants of the Thue--Morse sequence

Abstract: In 1998, Allouche, Peyri`ere, Wen and Wen established that the Hankel determinants associated with the Thue--Morse sequence on ${-1, 1}$ are always nonzero. Their proof depends on a set of sixteen recurrence relations. We present an alternative, purely combinatorial proof of the same result. We also re-prove a recent result of Coons on the non-vanishing of the Hankel determinants associated to two other classical integer sequences.