Christos Koukouvinos and Marilena Mitrouli have computed the GEP for some of the 487 inequivalent Hadamard matrices of order 28 on Neil Sloane's web page which were constructed by Kimura: Had.28.18 Automorphism group has order = 18 = 2 * 3^2 ps=(1, 2, 2, 4, 3, 10/3, 18/5, 4, 4, 5, 74/15, 508/111, 5.937, 5.069, 5.912, 5.447, 5.8408, 5.557, 6.4615, 28/3, 28/8, 28/4, 28/4, 28/2, 28/4, 28/2, 28/2, 28) Had.28.34 Automorphism group has order = 2 ps=(1, 2, 2, 4, 3, 10/3, 18/5, 4, 38/9, 4.5789, 5.1954, 5.4159, 4.9804, 4.7323, 5.9634, 5.25, 35/6, 8.4, 28/6, 28/3, 28/8, 28/4, 28/4, 28/2, 28/4, 28/2, 28/2, 28) All 487 matrices have the same SNF: 1,2^{13,14^{13},28. This page was created on 27th Novemeber 1999.