Let's evaluate: ∑k = 1n2k For ∑K = abc(K + d), the following formula applies: c(a + d)·c(b -a + 1) -1c -1 2·2(n -1 + 1) -12 -1 ℹ2·2(n -1 + 1) -12 -1 = 2·(2(n -1 + 1) -1)2 -1‖-1 + 1 = 0‖2 -1 = 1 2·(2(n + 0) -1)1 ▷Result: 2·(2n -1)