proposition: Lemma Nat2Z_pow (a b : nat) : Z.of_nat (a ^ b) = Z.of_nat a ^ Z.of_nat b.
proof: Proof. rewrite <-Zpower_nat_Z. induction b. easy. simpl. lia. Qed.
imports: Coq(ZArith Znumtheory Lia Psatz) Coqtail(Nlittle_fermat Ztools)