induction n; intuition; simpl in *.
destruct H; subst; intuition.
apply in_app_or in H;
destruct H;
apply in_map_iff in H;
destruct H;
intuition;
subst;
rewrite app_length; simpl;
rewrite plus_comm; simpl;
f_equal;
eapply IHn; eauto.
Qed.

(* Specifications: *)
Lemma getAllBlists_app_length_In : forall n ls,
length ls = n ->
In ls (getAllBlists_app n).