Sigma(30, 47, 83): A = 117030, e0 = -1, omega = [29, 1, 1], 32 vertices
  det(B) = 1, negative eigenvalues = 32 of 32, bad vertices = [0]
  (b) Laufer sequence on the lattice == closed formula on [0, N0+1] = [0, 109230]
      Nemethi Prop. 11.11 cycle == Laufer cycle and chi(full form) == tau at 110 samples
      semigroup form (Can-Karakurt) == closed formula on [0, N0]
  (c) K^2 + s = -102040, min tau = -12755, d = 0
  (d) union-find == stack: 853 bars, rank 4864
      HF_red = T(16)^1 + T(14)^10 + T(13)^16 + T(12)^24 + T(11)^36 + T(10)^46 + T(9)^56 + T(8)^66 + T(7)^76 + T(6)^82 + T(5)^84 + T(4)^86 + T(3)^88 + T(2)^90 + T(1)^92
      ell = 16, missing lengths: [15]
  (e) sigma(Milnor fibre) = -38912, sigma/8 = -4864, -(rank) - d/2 = -4864
