Add skew hadamard matrix of order 188

src/sage/combinat/designs/difference_family.py

@@ -2016,6 +2016,10 @@ def skew_supplementary_difference_set(n, existence=False, check=True):
              [2, 3, 4, 5, 9, 13, 15, 18, 19],
              [1, 2, 3, 4, 5, 6, 7, 8, 16],
              [1, 4, 6, 11, 12, 13, 15, 16, 17, 18]],
+        97: [[1, 2, 4, 6, 9, 11, 13, 14, 17, 18, 21, 23, 25, 27, 29, 30],
+             [1, 2, 6, 7, 8, 9, 10, 11, 12, 13, 23, 27, 29],
+             [0, 1, 2, 5, 6, 12, 13, 15, 16, 20, 24, 25, 26, 29, 30, 31],
+             [0, 2, 3, 4, 7, 8, 9, 11, 12, 13, 15, 16, 17, 18, 23, 28, 29]],
         103: [[1,3,4,6,8,11,12,14,17,18,20,22,25,27,28,30,32], 
               [2,9,10,12,13,14,15,16,20,21,22,23,24,26,28,29,30], 
               [0,1,2,3,4,11,12,13,16,17,19,20,21,24,25,26,28,30,31],
@@ -2079,6 +2083,7 @@ def skew_supplementary_difference_set(n, existence=False, check=True):
         65: [1, 2, 3, 5, 6, 7, 9, 10, 11, [13], 22, [26]],
         67: [1,2,3,4,5,6,8,10,12,15,17],
         93: [1, 2, 3, 5, 7, 9, 10, 14, 15, [31]],
+        97: [1, 2, 3, 4, 5, 6, 7, 9, 10, 12, 13, 15, 18, 20, 23, 26],
         103: [1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 14, 15, 17, 19, 21, 23, 30],
         113: [1, 2, 3, 5, 6, 9, 10, 13],
         121: [1, 2, 4, 5, 7, 8, 10, 11, 16, 17, 19, 20],
@@ -2103,6 +2108,7 @@ def skew_supplementary_difference_set(n, existence=False, check=True):
         65: [1, 16, 61],
         67: [1, 29, 37],
         93: [1, 4, 16, 64, 70],
+        97: [1, 35, 61],
         103: [1, 46, 56],
         113: [1,16,28,30,49,106,109],
         121: [1, 3, 9, 27, 81],