1. The problem statement, all variables and given/known data For n even, C(n,n/2)/(2^(N+1)) > 1/(2*sqrt(n)). 2. Relevant equations sqrt(2*pi*k) * k^k * e^-k < k! < sqrt(2*pi*k) * k^k * e^-k * (1 + 1/4*k) 3. The attempt at a solution Have tried using the inequality to get lower bound for C(n,n/2), but get something smaller than 1/(2*sqrt(n)).