isabelle/valid/mathd_numbertheory_461.thy (13 lines of code) (raw):

(* Authors: Wenda Li *) theory mathd_numbertheory_461 imports Complex_Main "HOL-Computational_Algebra.Computational_Algebra" "HOL-Number_Theory.Number_Theory" begin theorem mathd_numbertheory_461: fixes n :: nat assumes "n = card {k::nat. gcd k 8 = 1 \<and> 1\<le>k \<and> k < 8}" shows "(3^n) mod 8 = (1::nat)" sorry end