Cho dãy số xác định bởi u1 = 1; u(n + 1) = (1/3)(2un + (n - 1)/(n^2 + 3n + 2))

A. ${\mathrm{u}}_{2018}=\frac{2^{2016}}{3^{2017}}+\frac{1}{2019}$

B. ${\mathrm{u}}_{2018}=\frac{2^{2018}}{3^{2017}}+\frac{1}{2019}$

C. ${\mathrm{u}}_{2018}=\frac{2^{2017}}{3^{2018}}+\frac{1}{2018}$

D. ${\mathrm{u}}_{2018}=\frac{2^{2017}}{3^{2018}}+\frac{1}{2019}$