On the Existence of Multilevel Hadamard Matrices with Odd Order

The multilevel (n-ary) Hadamard matrices, which are related to orthogonal matrices or orthogonal designs, are investigated in this paper. It is assumed that all matrix elements are integers, which make the binary Hadamard matrices as special cases of multilevel (n-ary) Hadamard matrices. It is shown that the multilevel Hadamard matrices of odd order do exist if only two different matrix elements are contained; but, except an unknown case, multilevel (n-ary) Hadamard matrices of odd order do not exist when all matrix elements are successive integers.