Let E=(2n+1)(2n+3)(2n+5)⋯(4n–3)(4n–1) where n>1, then 2n E is divisible by
4nC2n
E=(2n+1)(2n+3)(2n+5)⋯(4n−3)(4n−1)E=(2n)!(2n+1)(2n+2)(2n+3)(2n+4)(2n+5)⋯(4n−1)4n(2n)!(2n+2)(2n+4)⋯(4n)E=(4n)!n!(2n)!n!2n(n+1)(n+2)⋯(2n)E=(4n)!n!(2n)!(2n)!2n⇒2nE=n!4nC2n
Hence 2nE is divisible by 4nC2n