∀ {k : ℕ} {x : ℝ},
  k ≠ 0 →
    x ∈ Set.Icc 0 1 →
      HurwitzZeta.hurwitzZeta (↑x) (1 - 2 * ↑k) =
        -1 / (2 * ↑k) * Polynomial.eval (↑x) (Polynomial.map (algebraMap ℚ ℂ) (Polynomial.bernoulli (2 * k)))