摘要
I. INTRODUCTION Let a set of s-distinct symbols be arranged in a s×s square in such a way that every symbol occurs exactly once in every row and every column. Such a square is called a Latin square of order s. Two Latin squares are called orthogonal if, when one of them is superposed on the other, every symbol of the first square occurs with every symbol of the second one once and only once. Now we denote by N(s)
