1. 2-bridge knots per crossing number (enumerated vs Ernst-Sumners):
   c=3: 1 vs 1
   c=4: 1 vs 1
   c=5: 2 vs 2
   c=6: 3 vs 3
   c=7: 7 vs 7
   c=8: 12 vs 12
   c=9: 24 vs 24
   c=10: 45 vs 45
   c=11: 91 vs 91
   c=12: 176 vs 176
2. floor-sum and Seifert-matrix signatures agree on all 362 knots (global sign relation sigma_F/sigma_S in {-1}); |det B| = p and Alexander polynomials agree.
3. 80 of them have |sigma| = 4, all with p = 1 mod 4, p >= 5; every square p has sigma = 0 mod 8.
4. minimal-crossing 2-bridge knots with det n and |sigma| = 4, n = 1 mod 4, 5 <= n <= 233:
   n=5: S(5,1), crossing number 5, Conway C(5,), Seifert V=[[-1, 1, 0, 0], [0, -1, 1, 0], [0, 0, -1, 1], [0, 0, 0, -1]]
   n=9: none (square)
   n=13: S(13,3), crossing number 7, Conway C(4, 3), Seifert V=[[-1, 1, 0, 0], [0, -1, 1, 0], [0, 0, -1, 1], [0, 0, 0, -2]]
   n=17: S(17,5), crossing number 7, Conway C(3, 2, 2), Seifert V=[[-1, 1, 0, 0], [0, -1, 1, 0], [0, 0, -2, 1], [0, 0, 0, -1]]
   n=21: S(21,4), crossing number 9, Conway C(5, 4), Seifert V=[[3, 1, 0, 0], [0, 1, 1, 0], [0, 0, 1, 1], [0, 0, 0, 1]]
   n=25: none (square)
   n=29: S(29,9), crossing number 9, Conway C(3, 4, 2), Seifert V=[[-1, 1, 0, 0], [0, -1, 1, 0], [0, 0, -3, 1], [0, 0, 0, -1]]
   n=33: S(33,7), crossing number 9, Conway C(4, 1, 2, 2), Seifert V=[[-1, 1, 0, 0, 0, 0], [0, -1, 1, 0, 0, 0], [0, 0, -1, 1, 0, 0], [0, 0, 0, -1, 1, 0], [0, 0, 0, 0, 1, 1], [0, 0, 0, 0, 0, -1]]
   n=37: S(37,10), crossing number 9, Conway C(3, 1, 2, 3), Seifert V=[[2, 1, 0, 0], [0, 2, 1, 0], [0, 0, 1, 1], [0, 0, 0, 1]]
   n=41: S(41,11), crossing number 9, Conway C(3, 1, 2, 1, 2), Seifert V=[[-1, 1, 0, 0, 0, 0], [0, -1, 1, 0, 0, 0], [0, 0, -1, 1, 0, 0], [0, 0, 0, 1, 1, 0], [0, 0, 0, 0, -1, 1], [0, 0, 0, 0, 0, -1]]
   n=45: S(45,19), crossing number 9, Conway C(2, 2, 1, 2, 2), Seifert V=[[-1, 1, 0, 0], [0, -2, 1, 0], [0, 0, -2, 1], [0, 0, 0, -1]]
   n=49: none (square)
   n=53: S(53,10), crossing number 11, Conway C(5, 3, 3), Seifert V=[[3, 1, 0, 0], [0, 1, 1, 0], [0, 0, 1, 1], [0, 0, 0, 2]]
   n=57: S(57,13), crossing number 10, Conway C(4, 2, 1, 1, 2), Seifert V=[[-1, 1, 0, 0, 0, 0], [0, -1, 1, 0, 0, 0], [0, 0, -1, 1, 0, 0], [0, 0, 0, -2, 1, 0], [0, 0, 0, 0, -1, 1], [0, 0, 0, 0, 0, 1]]
   n=61: S(61,22), crossing number 10, Conway C(2, 1, 3, 2, 2), Seifert V=[[1, 1, 0, 0, 0, 0], [0, -1, 1, 0, 0, 0], [0, 0, -1, 1, 0, 0], [0, 0, 0, -1, 1, 0], [0, 0, 0, 0, -2, 1], [0, 0, 0, 0, 0, -1]]
   n=65: S(65,19), crossing number 10, Conway C(3, 2, 2, 1, 2), Seifert V=[[-1, 1, 0, 0, 0, 0], [0, -1, 1, 0, 0, 0], [0, 0, -2, 1, 0, 0], [0, 0, 0, -1, 1, 0], [0, 0, 0, 0, -1, 1], [0, 0, 0, 0, 0, 1]]
   n=69: S(69,20), crossing number 11, Conway C(3, 2, 4, 2), Seifert V=[[2, 1, 0, 0], [0, 1, 1, 0], [0, 0, 3, 1], [0, 0, 0, 1]]
   n=73: S(73,13), crossing number 11, Conway C(5, 1, 1, 1, 1, 2), Seifert V=[[-1, 1, 0, 0, 0, 0, 0, 0], [0, -1, 1, 0, 0, 0, 0, 0], [0, 0, -1, 1, 0, 0, 0, 0], [0, 0, 0, -1, 1, 0, 0, 0], [0, 0, 0, 0, -1, 1, 0, 0], [0, 0, 0, 0, 0, 1, 1, 0], [0, 0, 0, 0, 0, 0, 1, 1], [0, 0, 0, 0, 0, 0, 0, -1]]
   n=77: S(77,16), crossing number 12, Conway C(4, 1, 4, 3), Seifert V=[[2, 1, 0, 0, 0, 0], [0, -1, 1, 0, 0, 0], [0, 0, -1, 1, 0, 0], [0, 0, 0, -1, 1, 0], [0, 0, 0, 0, -1, 1], [0, 0, 0, 0, 0, -2]]
   n=81: none (square)
   n=85: S(85,23), crossing number 11, Conway C(3, 1, 2, 3, 2), Seifert V=[[-1, 1, 0, 0, 0, 0], [0, -1, 1, 0, 0, 0], [0, 0, -1, 1, 0, 0], [0, 0, 0, 1, 1, 0], [0, 0, 0, 0, -2, 1], [0, 0, 0, 0, 0, -1]]
   n=89: S(89,24), crossing number 11, Conway C(3, 1, 2, 2, 3), Seifert V=[[2, 1, 0, 0], [0, 2, 1, 0], [0, 0, 1, 1], [0, 0, 0, 2]]
   n=93: S(93,25), crossing number 11, Conway C(3, 1, 2, 1, 1, 3), Seifert V=[[-1, 1, 0, 0, 0, 0], [0, -1, 1, 0, 0, 0], [0, 0, -1, 1, 0, 0], [0, 0, 0, 1, 1, 0], [0, 0, 0, 0, -1, 1], [0, 0, 0, 0, 0, -2]]
   n=97: S(97,21), crossing number 11, Conway C(4, 1, 1, 1, 1, 1, 2), Seifert V=[[-1, 1, 0, 0, 0, 0, 0, 0], [0, -1, 1, 0, 0, 0, 0, 0], [0, 0, -1, 1, 0, 0, 0, 0], [0, 0, 0, -1, 1, 0, 0, 0], [0, 0, 0, 0, 1, 1, 0, 0], [0, 0, 0, 0, 0, 1, 1, 0], [0, 0, 0, 0, 0, 0, -1, 1], [0, 0, 0, 0, 0, 0, 0, -1]]
   n=101: S(101,30), crossing number 11, Conway C(3, 2, 1, 2, 1, 2), Seifert V=[[2, 1, 0, 0, 0, 0], [0, 1, 1, 0, 0, 0], [0, 0, 1, 1, 0, 0], [0, 0, 0, -1, 1, 0], [0, 0, 0, 0, 1, 1], [0, 0, 0, 0, 0, 1]]
   n=105: S(105,29), crossing number 11, Conway C(3, 1, 1, 1, 1, 1, 3), Seifert V=[[-1, 1, 0, 0, 0, 0, 0, 0], [0, -1, 1, 0, 0, 0, 0, 0], [0, 0, -1, 1, 0, 0, 0, 0], [0, 0, 0, 1, 1, 0, 0, 0], [0, 0, 0, 0, 1, 1, 0, 0], [0, 0, 0, 0, 0, -1, 1, 0], [0, 0, 0, 0, 0, 0, -1, 1], [0, 0, 0, 0, 0, 0, 0, -1]]
   n=109: S(109,45), crossing number 11, Conway C(2, 2, 2, 1, 2, 2), Seifert V=[[-1, 1, 0, 0, 0, 0], [0, -2, 1, 0, 0, 0], [0, 0, -1, 1, 0, 0], [0, 0, 0, -1, 1, 0], [0, 0, 0, 0, 1, 1], [0, 0, 0, 0, 0, -1]]
   n=113: S(113,21), crossing number 12, Conway C(5, 2, 1, 1, 1, 2), Seifert V=[[-1, 1, 0, 0, 0, 0, 0, 0], [0, -1, 1, 0, 0, 0, 0, 0], [0, 0, -1, 1, 0, 0, 0, 0], [0, 0, 0, -1, 1, 0, 0, 0], [0, 0, 0, 0, -2, 1, 0, 0], [0, 0, 0, 0, 0, -1, 1, 0], [0, 0, 0, 0, 0, 0, 1, 1], [0, 0, 0, 0, 0, 0, 0, 1]]
   n=117: S(117,43), crossing number 11, Conway C(2, 1, 2, 1, 1, 2, 2), Seifert V=[[-1, 1, 0, 0, 0, 0], [0, -1, 1, 0, 0, 0], [0, 0, 1, 1, 0, 0], [0, 0, 0, -1, 1, 0], [0, 0, 0, 0, -2, 1], [0, 0, 0, 0, 0, -1]]
   n=121: none (square)
   n=125: S(125,49), crossing number 12, Conway C(2, 1, 1, 4, 2, 2), Seifert V=[[-1, 1, 0, 0, 0, 0, 0, 0], [0, -1, 1, 0, 0, 0, 0, 0], [0, 0, 1, 1, 0, 0, 0, 0], [0, 0, 0, 1, 1, 0, 0, 0], [0, 0, 0, 0, 1, 1, 0, 0], [0, 0, 0, 0, 0, 1, 1, 0], [0, 0, 0, 0, 0, 0, 2, 1], [0, 0, 0, 0, 0, 0, 0, 1]]
   n=129: S(129,53), crossing number 12, Conway C(2, 2, 3, 3, 2), Seifert V=[[-1, 1, 0, 0, 0, 0], [0, -2, 1, 0, 0, 0], [0, 0, -1, 1, 0, 0], [0, 0, 0, -1, 1, 0], [0, 0, 0, 0, -2, 1], [0, 0, 0, 0, 0, 1]]
   n=133: S(133,36), crossing number 12, Conway C(3, 1, 2, 3, 1, 2), Seifert V=[[2, 1, 0, 0, 0, 0], [0, 2, 1, 0, 0, 0], [0, 0, 1, 1, 0, 0], [0, 0, 0, 1, 1, 0], [0, 0, 0, 0, 1, 1], [0, 0, 0, 0, 0, -1]]
   n=137: S(137,29), crossing number 12, Conway C(4, 1, 2, 1, 1, 1, 2), Seifert V=[[-1, 1, 0, 0, 0, 0, 0, 0], [0, -1, 1, 0, 0, 0, 0, 0], [0, 0, -1, 1, 0, 0, 0, 0], [0, 0, 0, -1, 1, 0, 0, 0], [0, 0, 0, 0, 1, 1, 0, 0], [0, 0, 0, 0, 0, -1, 1, 0], [0, 0, 0, 0, 0, 0, -1, 1], [0, 0, 0, 0, 0, 0, 0, 1]]
   n=141: S(141,41), crossing number 12, Conway C(3, 2, 3, 1, 1, 2), Seifert V=[[-1, 1, 0, 0, 0, 0, 0, 0], [0, -1, 1, 0, 0, 0, 0, 0], [0, 0, -2, 1, 0, 0, 0, 0], [0, 0, 0, -1, 1, 0, 0, 0], [0, 0, 0, 0, -1, 1, 0, 0], [0, 0, 0, 0, 0, -1, 1, 0], [0, 0, 0, 0, 0, 0, 1, 1], [0, 0, 0, 0, 0, 0, 0, 1]]
   n=145: S(145,44), crossing number 12, Conway C(3, 3, 2, 1, 1, 2), Seifert V=[[2, 1, 0, 0, 0, 0], [0, 1, 1, 0, 0, 0], [0, 0, 1, 1, 0, 0], [0, 0, 0, 2, 1, 0], [0, 0, 0, 0, 1, 1], [0, 0, 0, 0, 0, -1]]
   n=149: S(149,26), crossing number 13, Conway C(5, 1, 2, 1, 2, 2), Seifert V=[[3, 1, 0, 0], [0, 2, 1, 0], [0, 0, 2, 1], [0, 0, 0, 1]]
   n=153: S(153,41), crossing number 12, Conway C(3, 1, 2, 1, 2, 1, 2), Seifert V=[[-1, 1, 0, 0, 0, 0, 0, 0], [0, -1, 1, 0, 0, 0, 0, 0], [0, 0, -1, 1, 0, 0, 0, 0], [0, 0, 0, 1, 1, 0, 0, 0], [0, 0, 0, 0, -1, 1, 0, 0], [0, 0, 0, 0, 0, -1, 1, 0], [0, 0, 0, 0, 0, 0, -1, 1], [0, 0, 0, 0, 0, 0, 0, 1]]
   n=157: S(157,46), crossing number 12, Conway C(3, 2, 2, 2, 1, 2), Seifert V=[[2, 1, 0, 0, 0, 0], [0, 1, 1, 0, 0, 0], [0, 0, 2, 1, 0, 0], [0, 0, 0, 1, 1, 0], [0, 0, 0, 0, 1, 1], [0, 0, 0, 0, 0, -1]]
   n=161: S(161,30), crossing number 13, Conway C(5, 2, 1, 2, 1, 2), Seifert V=[[3, 1, 0, 0, 0, 0], [0, 1, 1, 0, 0, 0], [0, 0, 1, 1, 0, 0], [0, 0, 0, -1, 1, 0], [0, 0, 0, 0, 1, 1], [0, 0, 0, 0, 0, 1]]
   n=165: S(165,49), crossing number 12, Conway C(3, 2, 1, 2, 1, 1, 2), Seifert V=[[-1, 1, 0, 0, 0, 0], [0, -1, 1, 0, 0, 0], [0, 0, -2, 1, 0, 0], [0, 0, 0, -2, 1, 0], [0, 0, 0, 0, -1, 1], [0, 0, 0, 0, 0, 1]]
   n=169: none (square)
   n=173: S(173,64), crossing number 12, Conway C(2, 1, 2, 2, 1, 2, 2), Seifert V=[[1, 1, 0, 0, 0, 0], [0, -1, 1, 0, 0, 0], [0, 0, -1, 1, 0, 0], [0, 0, 0, -2, 1, 0], [0, 0, 0, 0, -2, 1], [0, 0, 0, 0, 0, -1]]
   n=177: S(177,37), crossing number 13, Conway C(4, 1, 3, 1, 1, 1, 2), Seifert V=[[-1, 1, 0, 0, 0, 0, 0, 0], [0, -1, 1, 0, 0, 0, 0, 0], [0, 0, -1, 1, 0, 0, 0, 0], [0, 0, 0, -1, 1, 0, 0, 0], [0, 0, 0, 0, 2, 1, 0, 0], [0, 0, 0, 0, 0, 1, 1, 0], [0, 0, 0, 0, 0, 0, -1, 1], [0, 0, 0, 0, 0, 0, 0, -1]]
   n=181: S(181,70), crossing number 12, Conway C(2, 1, 1, 2, 2, 2, 2), Seifert V=[[1, 1, 0, 0, 0, 0], [0, -1, 1, 0, 0, 0], [0, 0, -2, 1, 0, 0], [0, 0, 0, -1, 1, 0], [0, 0, 0, 0, -2, 1], [0, 0, 0, 0, 0, -1]]
   n=185: S(185,56), crossing number 13, Conway C(3, 3, 3, 2, 2), Seifert V=[[2, 1, 0, 0, 0, 0], [0, 1, 1, 0, 0, 0], [0, 0, 1, 1, 0, 0], [0, 0, 0, 2, 1, 0], [0, 0, 0, 0, -1, 1], [0, 0, 0, 0, 0, 1]]
   n=189: S(189,41), crossing number 13, Conway C(4, 1, 1, 1, 1, 3, 2), Seifert V=[[-1, 1, 0, 0, 0, 0, 0, 0], [0, -1, 1, 0, 0, 0, 0, 0], [0, 0, -1, 1, 0, 0, 0, 0], [0, 0, 0, -1, 1, 0, 0, 0], [0, 0, 0, 0, 1, 1, 0, 0], [0, 0, 0, 0, 0, 1, 1, 0], [0, 0, 0, 0, 0, 0, -2, 1], [0, 0, 0, 0, 0, 0, 0, -1]]
   n=193: S(193,41), crossing number 13, Conway C(4, 1, 2, 2, 2, 2), Seifert V=[[-1, 1, 0, 0, 0, 0, 0, 0], [0, -1, 1, 0, 0, 0, 0, 0], [0, 0, -1, 1, 0, 0, 0, 0], [0, 0, 0, -1, 1, 0, 0, 0], [0, 0, 0, 0, 1, 1, 0, 0], [0, 0, 0, 0, 0, -1, 1, 0], [0, 0, 0, 0, 0, 0, 1, 1], [0, 0, 0, 0, 0, 0, 0, -1]]
   n=197: S(197,43), crossing number 13, Conway C(4, 1, 1, 2, 1, 1, 3), Seifert V=[[-1, 1, 0, 0, 0, 0, 0, 0, 0, 0], [0, -1, 1, 0, 0, 0, 0, 0, 0, 0], [0, 0, -1, 1, 0, 0, 0, 0, 0, 0], [0, 0, 0, -1, 1, 0, 0, 0, 0, 0], [0, 0, 0, 0, 1, 1, 0, 0, 0, 0], [0, 0, 0, 0, 0, 1, 1, 0, 0, 0], [0, 0, 0, 0, 0, 0, 1, 1, 0, 0], [0, 0, 0, 0, 0, 0, 0, -1, 1, 0], [0, 0, 0, 0, 0, 0, 0, 0, -1, 1], [0, 0, 0, 0, 0, 0, 0, 0, 0, -1]]
   n=201: S(201,46), crossing number 13, Conway C(4, 2, 1, 2, 2, 2), Seifert V=[[2, 1, 0, 0, 0, 0], [0, -1, 1, 0, 0, 0], [0, 0, 1, 1, 0, 0], [0, 0, 0, 1, 1, 0], [0, 0, 0, 0, 2, 1], [0, 0, 0, 0, 0, 1]]
   n=205: S(205,61), crossing number 13, Conway C(3, 2, 1, 3, 2, 2), Seifert V=[[-1, 1, 0, 0, 0, 0], [0, -1, 1, 0, 0, 0], [0, 0, -2, 1, 0, 0], [0, 0, 0, -2, 1, 0], [0, 0, 0, 0, 1, 1], [0, 0, 0, 0, 0, -1]]
   n=209: S(209,56), crossing number 13, Conway C(3, 1, 2, 1, 2, 1, 3), Seifert V=[[2, 1, 0, 0], [0, 2, 1, 0], [0, 0, 2, 1], [0, 0, 0, 2]]
   n=213: S(213,59), crossing number 13, Conway C(3, 1, 1, 1, 1, 3, 3), Seifert V=[[-1, 1, 0, 0, 0, 0, 0, 0], [0, -1, 1, 0, 0, 0, 0, 0], [0, 0, -1, 1, 0, 0, 0, 0], [0, 0, 0, 1, 1, 0, 0, 0], [0, 0, 0, 0, 1, 1, 0, 0], [0, 0, 0, 0, 0, -2, 1, 0], [0, 0, 0, 0, 0, 0, -1, 1], [0, 0, 0, 0, 0, 0, 0, -1]]
   n=217: S(217,47), crossing number 13, Conway C(4, 1, 1, 1, 1, 1, 1, 3), Seifert V=[[-1, 1, 0, 0, 0, 0, 0, 0], [0, -1, 1, 0, 0, 0, 0, 0], [0, 0, -1, 1, 0, 0, 0, 0], [0, 0, 0, -1, 1, 0, 0, 0], [0, 0, 0, 0, 1, 1, 0, 0], [0, 0, 0, 0, 0, 1, 1, 0], [0, 0, 0, 0, 0, 0, -1, 1], [0, 0, 0, 0, 0, 0, 0, -2]]
   n=221: S(221,41), crossing number 14, Conway C(5, 2, 1, 1, 3, 2), Seifert V=[[-1, 1, 0, 0, 0, 0, 0, 0], [0, -1, 1, 0, 0, 0, 0, 0], [0, 0, -1, 1, 0, 0, 0, 0], [0, 0, 0, -1, 1, 0, 0, 0], [0, 0, 0, 0, -2, 1, 0, 0], [0, 0, 0, 0, 0, -1, 1, 0], [0, 0, 0, 0, 0, 0, 2, 1], [0, 0, 0, 0, 0, 0, 0, 1]]
   n=225: none (square)
   n=229: S(229,64), crossing number 13, Conway C(3, 1, 1, 2, 1, 2, 3), Seifert V=[[2, 1, 0, 0, 0, 0], [0, 1, 1, 0, 0, 0], [0, 0, -1, 1, 0, 0], [0, 0, 0, 1, 1, 0], [0, 0, 0, 0, 1, 1], [0, 0, 0, 0, 0, 2]]
   n=233: S(233,84), crossing number 13, Conway C(2, 1, 3, 2, 2, 1, 2), Seifert V=[[1, 1, 0, 0, 0, 0, 0, 0], [0, -1, 1, 0, 0, 0, 0, 0], [0, 0, -1, 1, 0, 0, 0, 0], [0, 0, 0, -1, 1, 0, 0, 0], [0, 0, 0, 0, -2, 1, 0, 0], [0, 0, 0, 0, 0, -1, 1, 0], [0, 0, 0, 0, 0, 0, -1, 1], [0, 0, 0, 0, 0, 0, 0, 1]]
5. S(8d-3, 4) has |det| = 8d-3 and |sigma| = 4 for d = 1..399 (both formulas).
   S(n,10) for n = 13 mod 20 (400 values): Seifert form = chain (2B,2,2,4), positive definite, |det| = n, sigma = 4.
   S(n,10) for n = 17 mod 20 (400 values): Seifert form = chain (2B,4,2,2), positive definite, |det| = n, sigma = 4.
   S(n,12) for n = 17 mod 24 (400 values): Seifert form = chain (2B,2,4,2), positive definite, |det| = n, sigma = 4.
6. primes p = 1 mod 24 in [2857, 4000]: minimal-crossing 2-bridge knot with |sigma| = 4:
   p=2857: S(2857,652), crossing number 19, Conway C(4, 2, 1, 1, 1, 1, 1, 1, 1, 3, 3)
   p=2953: S(2953,877), crossing number 18, Conway C(3, 2, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 2)
   p=3001: S(3001,1103), crossing number 18, Conway C(2, 1, 2, 1, 1, 2, 1, 1, 2, 1, 1, 1, 2)
   p=3049: S(3049,1128), crossing number 18, Conway C(2, 1, 2, 2, 1, 2, 1, 1, 1, 1, 1, 1, 2)
   p=3121: S(3121,1192), crossing number 18, Conway C(2, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 2, 2)
   p=3169: S(3169,851), crossing number 19, Conway C(3, 1, 2, 1, 1, 1, 1, 1, 3, 1, 1, 3)
   p=3217: S(3217,884), crossing number 19, Conway C(3, 1, 1, 1, 3, 2, 1, 2, 2, 1, 2)
   p=3313: S(3313,1174), crossing number 19, Conway C(2, 1, 4, 1, 1, 1, 1, 1, 1, 2, 1, 1, 2)
   p=3361: S(3361,1283), crossing number 19, Conway C(2, 1, 1, 1, 1, 1, 2, 3, 2, 3, 2)
   p=3433: S(3433,920), crossing number 19, Conway C(3, 1, 2, 1, 2, 1, 1, 1, 2, 1, 1, 3)
   p=3457: S(3457,1026), crossing number 19, Conway C(3, 2, 1, 2, 2, 2, 2, 2, 1, 2)
   p=3529: S(3529,1254), crossing number 19, Conway C(2, 1, 4, 2, 1, 1, 1, 1, 1, 1, 1, 1, 2)
   p=3673: S(3673,1086), crossing number 19, Conway C(3, 2, 1, 1, 1, 1, 1, 1, 3, 2, 1, 2)
   p=3697: S(3697,1022), crossing number 19, Conway C(3, 1, 1, 1, 1, 1, 1, 2, 3, 2, 1, 2)
   p=3769: S(3769,822), crossing number 20, Conway C(4, 1, 1, 2, 2, 3, 2, 1, 1, 3)
   p=3793: S(3793,1050), crossing number 19, Conway C(3, 1, 1, 1, 1, 2, 1, 1, 1, 2, 2, 3)
   p=3889: S(3889,1148), crossing number 19, Conway C(3, 2, 1, 1, 2, 1, 1, 1, 2, 1, 2, 2)
PYTHONDONTWRITEBYTECODE=1 python3 twobridge.py 12 233  2.88s user 0.02s system 99% cpu 2.904 total
