revert m
b k m n : ℕ
hm : 0 < m
hb : 1 < b
⊢ b.digits n ++ List.replicate k 0 ++ b.digits m = b.digits (n + b ^ (k + (b.digits n).length) * m)
b k n : ℕ
hb : 1 < b
⊢ ∀ {m : ℕ}, 0 < m → b.digits n ++ List.replicate k 0 ++ b.digits m = b.digits (n + b ^ (k + (b.digits n).length) * m)