isabelle/valid/mathd_numbertheory_109.thy (12 lines of code) (raw):

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