proposition: Lemma exp2_log_even n: ~~ odd (2 ^(log2 n.+1)).
proof: Proof. by rewrite (log2S_k n) expn2S odd_double. 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)