isabelle/valid/numbertheory_2dvd4expn.thy (12 lines of code) (raw):

(* Authors: Albert Qiaochu Jiang *) theory numbertheory_2dvd4expn imports Complex_Main begin theorem numbertheory_2dvd4expn: fixes n :: nat assumes h0 : "n \<noteq> 0" shows "(2::nat) dvd 4^n" sorry end