An Infinite Class of Williamson Matrices

Abstract Only a finite number of Hadamard matrices of Williamson type are known so far; it has been conjectured that one such exists of any order 4 t . An infinite family is constructed here, and as a corollary it is shown that an Hadamard matrix of order 6( q + 1) exists if q is a prime power ≡ 1 (mod 4).