proposition: Lemma fusc_succ_pow2 n: fusc ((2^n).+1) = n.+1.
proof: Proof. by elim: n => [// | n IHn]; rewrite expn2S fusc_odd IHn fusc_pow2. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat) mathcomp(seq choice fintype order bigop ssralg) mathcomp(div ssrnum ssrint rat prime path binomial) mathcomp(tuple finset) gaia(fibm)