proposition: Lemma FR_fib2 k: FR (fib k.*2.+1) = FR (fib k.*2).
proof: Proof. by case k; [rewrite FR_1 FR_0 | apply: FR_fib1 ]. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat) mathcomp(seq path fintype div bigop binomial) mathcomp(prime finset ssralg ssrnum ssrint)