isabelle/valid/induction_sum2kp1npqsqm1.thy (12 lines of code) (raw):
(*
Authors: Wenda Li
*)
theory induction_sum2kp1npqsqm1
imports Complex_Main "HOL-Computational_Algebra.Computational_Algebra"
"HOL-Number_Theory.Number_Theory"
begin
theorem induction_sum2kp1npqsqm1:
fixes n :: nat
shows "(\<Sum> k<n. 2 * k + 3) = (n + 1)^2 - 1"
sorry
end