proposition: Lemma FR_fib_sum7 i: FR(fib (i + 6) + 3) = (i.+3)./2 + (i.+4)./2.
proof: Proof. by rewrite (FR_fib_sum1 i) //= mul1n. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat) mathcomp(seq path fintype div bigop binomial) mathcomp(prime finset ssralg ssrnum ssrint)