x[n] = {..., 0.5^{−3}, 0.5^{−2}, 0.5^{−1}, 1, 0.5, 0.5^{2}, 0.5^{3}, ...} = {..., 2^{3}, 2^{2}, 2, 1, 0.5, 0.5^{2}, 0.5^{3}, ...}