2 (3 + 13*n)
(3 + 13*n)^2 при n = 1/3
(3 + 13*n)^2
(3 + 13*(1/3))^2
(3 + 13/3)^2
484/9
(3.0 + 13.0*n)^2
2 9 + 78*n + 169*n