$${E_P = \frac{1}{2} E_1 + \bigg(\frac{1}{2} E_1 - E_2 + \frac{1}{2} E_3 \bigg) + \bigg(\frac{1}{2} E_3 - E_4 + \frac{1}{2} E_5 \bigg) + \bigg(\frac{1}{2} E_5 - E_6 + \frac{1}{2} E_7 \bigg) + ...}$$