proposition: Lemma sorted_ggen_sdouble n: sorted ggen (rev (mkseq double n)).
proof: Proof. by rewrite rev_sorted; apply:sorted_llen_mkseq_e. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat) mathcomp(seq path fintype div bigop binomial) mathcomp(prime finset ssralg ssrnum ssrint)