ABSTRACT
It was unknown whether a W (\l, 9) exists or not (see Craigen, 1996). Recently, Ohmori and Miyamoto (1997) have constructed a W(Y1, 9). On
the other hand, it is easy to show that a necessary condition for the existence of a Hadamard matrix of order n is η = 1,2 or n = 4i, where t is a positive integer. Hadamard (1893) conjectured that the condition is also sufficient. The smallest order which is unknown whether Hadamard’s conjecture is correct or not is 428 (Craigen, 1996).
