Amicable Hadamard Matrices

Abstract If X is a symmetric Hadamard matrix, Y is a skew-Hadamard matrix, and XY T is symmetric, then X and Y are said to be amicable Hadamard matrices. A construction for amicable Hadamard matrices is given, and then amicable Hadamard matrices are used to generalize a construction for skew-Hadamard matrices.