A sequence is quadratic if its terms have the explicit form a_{n} = An^{2} + Bn + C. The first three terms of the given sequence are a_{1} = 11, a_{2} = 14, and a_{3} = 19. Substituting these into the explicit form gives a system of three equations in three variables:

11 = A + B + C

14 = 4A + 2B + C

19 = 9A + 3B + C

Solve this system to get A = 1, B = 0, C = 10, which means that a_{n} = n^{2} + 10.