 Perturbation series in quantum field theory are usually divergent as was firstly indicated by Freeman Dyson.According to the Lipatov method, formula_5-th order contribution of perturbation theory into any quantity can be evaluated at large formula_5 in the saddle-point approximation for functional integrals and is determined by instanton configurations.This contribution behaves usually as formula_7 in dependence on formula_5 and is frequently associated with approximately the same (formula_7) number of Feynman diagrams.