(* Authors: Wenda Li *) theory mathd_numbertheory_109 imports Complex_Main "HOL-Computational_Algebra.Computational_Algebra" begin theorem mathd_numbertheory_109: fixes v :: "nat \ nat" assumes "\ n. v n = 2 * n - 1" shows "(\ k \{1..<101}. v k) mod 7 = 4" sorry end