Math Comment [(n-0)! /(n-2×0)!]÷0! + [(n-1)!/(n-2×1)!]÷1! +[(n-2)!/(n-2×2)!]÷2! + ....................+ [(n-(n÷2))!/(n-n)!]÷(n÷2)! Reply
[(n-0)! /(n-2×0)!]÷0! + [(n-1)!/(n-2×1)!]÷1! +[(n-2)!/(n-2×2)!]÷2! + ....................+ [(n-(n÷2))!/(n-n)!]÷(n÷2)!