[ Eq(Derivative(x1, t), (-1)*k18*k1*x1*x16/k18),
  Eq(Derivative(x2, t), (1*k18*k1*x1*x16 + (-1)*k18*k2*x2*x8 + (-1)*k18*k3*x2*x17 + (-1)*k18*k4*x2*x18)/k18),
  Eq(Derivative(x3, t), (1*k18*k2*x2*x8 + (-1)*k18*k5*x3*x8 + (-1)*k18*k6*x3*x17 + (-1)*k18*k7*x3*x18)/k18),
  Eq(Derivative(x4, t), (1*k18*k3*x2*x17 + (-1)*k18*k5*x4*x8 + (-1)*k18*k6*x4*x17 + (-1)*k18*k7*x4*x18)/k18),
  Eq(Derivative(x5, t), (1*k18*k4*x2*x18 + (-1)*k18*k5*x5*x8 + (-1)*k18*k6*x5*x17 + (-1)*k18*k7*x5*x18)/k18),
  Eq(Derivative(x6, t), (1*k18*k5*x3*x8 + (-1)*k18*k8*x6*x6 + 1*k18*k10*x8*x10)/k18),
  Eq(Derivative(x7, t), (-1)*k18*k9*x7*x9/k18),
  Eq(Derivative(x8, t), ((-1)*k18*k2*x2*x8 + (-1)*k18*k5*x3*x8 + (-1)*k18*k5*x4*x8 + (-1)*k18*k5*x5*x8 + (-1)*k18*k10*x8*x10)/k18),
  Eq(Derivative(x9, t), (1*k18*k8*x6*x6 + (-1)*k18*k11*x9)/k18),
  Eq(Derivative(x10, t), (1*k18*k9*x7*x9 + (-1)*k18*k12*x10)/k18),
  Eq(Derivative(x11, t), (1*k18*k6*x3*x17 + 1*k18*k5*x4*x8 + (-1)*k18*k13*x11*x19)/k18),
  Eq(Derivative(x12, t), (-1)*k18*k14*x12*x14/k18),
  Eq(Derivative(x13, t), (1*k18*k14*x12*x14 + (-1)*k18*k15*x13)/k18),
  Eq(Derivative(x14, t), (1*k18*k13*x11*x19 + (-1)*k18*k16*x14)/k18),
  Eq(Derivative(x15, t), (1*k18*k15*x13 + (-1)*k18*k17*x15)/k18),
  Eq(Derivative(x16, t), (-1)*k18*k1*x1*x16/k18),
  Eq(Derivative(x17, t), ((-1)*k18*k3*x2*x17 + (-1)*k18*k6*x3*x17 + (-1)*k18*k6*x4*x17 + (-1)*k18*k6*x5*x17)/k18),
  Eq(Derivative(x18, t), ((-1)*k18*k4*x2*x18 + (-1)*k18*k7*x3*x18 + (-1)*k18*k7*x4*x18 + (-1)*k18*k7*x5*x18)/k18),
  Eq(Derivative(x19, t), (-1)*k18*k13*x11*x19/k18),
  Eq(Derivative(x20, t), (1*k18*k7*x3*x18 + 1*k18*k5*x5*x8)/k18),
  Eq(Derivative(x21, t), 1*k18*k6*x4*x17/k18),
  Eq(Derivative(x22, t), (1*k18*k7*x4*x18 + 1*k18*k6*x5*x17)/k18),
  Eq(Derivative(x23, t), 1*k18*k7*x5*x18/k18) ]