proposition: Lemma coprimeSn_fib n: coprime (fib n) (fib n.+1) .
proof: Proof. by elim:n =>// h; rewrite /coprime fibSS gcdnDl gcdnC. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat) mathcomp(seq path fintype div bigop binomial) mathcomp(prime finset ssralg ssrnum ssrint)