Opaque DivTwoPower'_e.
Definition DivTwoPower_e : Cobham :=
Comp 2 DivTwoPower'_e [Proj 2 1; Proj 2 0].

Lemma DivTwoPower_correct : forall l,
Sem DivTwoPower_e l =
skipn (length (nth 1 l nil)) (nth 0 l nil).