Skew-Hadamard matrices of orders 188 and 388 exist

Authors :: Djokovic, Dragomir Z.
Source :: International Mathematical Forum 3 (2008), no. 22, 1063-1068
Publication Year :: 2007
Abstract: We construct several difference families on cyclic groups of orders 47 and 97, and use them to construct skew-Hadamard matrices of orders 188 and 388. Such difference families and matrices are constructed here for the first time. The matrices are constructed by using the Goethals-Seidel array.<br />Comment: 7 pages, no figures, a paragraph added to the introduction, two misprints corrected. To appear in the International Mathematical Forum