TOMATO
Suppose that x1, x2, …., xn (n > 2) are real numbers such that xi = Xn-i+1 for 1 ≤ i ≤ n. Consider the sum S = ΣΣΣxixjxk, where summations are taken over all i, j, k : 1 ≤ i, j, k ≤ n and i, j, k are all distinct. Then S equals
Suppose that x1, x2, …., xn (n 2) are real numbers such that xi= Xn-i+1 for 1 ≤ i ≤ n. Consider the sum S = ΣΣΣxixjxk, wheresummations are taken over all i, j, ...