isabelle/valid/mathd_numbertheory_149.thy (11 lines of code) (raw):

(* Authors: Wenda Li *) theory mathd_numbertheory_149 imports Complex_Main "HOL-Computational_Algebra.Computational_Algebra" "HOL-Number_Theory.Number_Theory" begin theorem mathd_numbertheory_149: "(\<Sum> k\<in> {x::nat. x<50 \<and> x mod 8 =5 \<and> x mod 6=3}. k) = 66" sorry end