[en] A numerically exact scheme of calculation of light nuclei is developed in the basis of the main harmonic and of all potential harmonics with the use of pair-correlation operators. All approximations are evaluated and the P model is improved. In a numerically exact scheme the ¹⁶O nucleus is calculated with different variants of a realistic NN interaction. Reasonable agreement with the results of the method of bound clusters is found. It is shown that more accurate calculations do not change the conclusion that a simultaneous description of the binding energy and the radius of light nuclei with a unique NN interaction is impossible