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