proposition: Lemma FR_fib1 k: FR (fib k.*2.+3) = FR (fib k.*2.+2).
proof: Proof. by rewrite FR_prop3 /Zeck_li ?Zeck_fib ?Zeckp_fib //= odd_double. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat) mathcomp(seq path fintype div bigop binomial) mathcomp(prime finset ssralg ssrnum ssrint)