apply decide_eq_decide.mpr
k : Nat
h_ind : ∀ (i : Nat), getBit (2 ^ k - 1) i = decide (i < k)
⊢ decide ((2 ^ succ k - 1) % 2 = 1) = decide (0 < succ k)
k : Nat
h_ind : ∀ (i : Nat), getBit (2 ^ k - 1) i = decide (i < k)
⊢ (2 ^ succ k - 1) % 2 = 1 ↔ 0 < succ k