  In the present paper by using Mathematica system a symbolic programming
method for generation of the expressions of the expansion terms of atomic
stationary perturbation theory (PT) is presented. For this purpose, the package
named as NCoperators was developed. In producing the PT terms, this package
accommodates the features of the Rayleigh-Schr\"odinger perturbation theory
(RSPT), the second quantization method (SQR) and angular momentum theory (AMT).
The package was built in such a way that it could be applicable in various
areas of theoretical atomic spectroscopy. Many functions of the NCoperators can
be easily adapted for users to their own demand by easily transforming the
functions developed. The package gives a possibility of generating formulas in
traditional output form. For some quantities the expressions obtained in
Mathematica can be converted into C code. Although the NCoperators package was
developed for Unix OS, it can be easily adopted for other OSs if some of the
parameters to be changed.
