The occurrence and quantitative properties of Seyfert 1 and Seyfert 2 galaxies as a function of the galaxy environment have been studied in a systematic way. For this investigation we have selected from the Catalogue of Quasars and Active Nuclei (Veron & Veron, 1989) all Seyfert galaxies with the following properties:
(i) mV ≤ 15,
(ii) listed classification as Sey 1, Sey 2, or Sey 3,
(iii) vrad ≤ 20000 km s-1.
This results in a sample size of 242 Seyfert galaxies. For all these objects their galaxy environment has been inspected on POSS and ESO/SRC plates.
The vicinity of each sample Seyfert galaxy was searched for companion galaxies out to at least 0.5 Mpc. Lacking redshift information we adopted as a companion galaxy any galaxy in this area having a size between 20 and 200 percent of the Seyfert galaxy size.