A (-1, 1)-matrix is a matrix whose elements consist only of the numbers -1 or 1. For an n×n (-1, 1)-matrix, the largest possible determinants (Hadamard's maximum determinant problem) for n = 1, 2, ... are 1, 2, 4, 16, 48, 160, ... (OEIS A003433, Ehrlich 1964), the same as for an n×n (-1, 0, 1)-matrix. The numbers of distinct n×n (-1, 1)-matrices having the largest possible determinant are 1, 4, 96, 384, 30720, ... (OEIS A188895).

Hadamard matrix | integer matrix