Enumeration of Polyhex Hydrocarbons to h = 17

A classical paper on the enumeration of polvhex h1'drocarbonsr dates back to 1968. But it was not befbre 1983 that the Diisseldorf-Zagreb group (Krop and Trinajsti6 with collaborators), inspired by Balasubramanian et al.,r published their results3 from compurerized enumerations of geometrically planar, simply connected polyhexes to ir : 10, where /z is the number of hexagons. The results for lr : 1 I came from Novi Sad,a while the h : 12 data emerged from a Chinese-Norwegian collaboration.t Gutman6 emphasized the difficulties in computations of this kind fbr large ft values and proposed therefore an empirical function, which was supposed to reproduce approximate N(ft) numbers of the polyhexes under consideration. However. his fbrmula, which was based on exact N(ft) numbers for ft I I in the works cited above. The present alsorithm uses the results of the enumeration and classifica-