cp's OEIS Frontend

A045903 Number of nonisomorphic systems of catafusenes in an example in Cyvin et al. (1994) with two appendages to the core indexed by the total number of hexagons in the appendages.

%I A045903 #27 Feb 16 2025 08:32:38
%S A045903 0,0,2,5,26,101,457,1978,8851,39481,178043
%N A045903 Number of nonisomorphic systems of catafusenes in an example in Cyvin et al. (1994) with two appendages to the core indexed by the total number of hexagons in the appendages.
%C A045903 From _Petros Hadjicostas_, May 25 2019: (Start)
%C A045903 This is column alpha = 2 in Table 5 on p. 1179 of Cyvin et al. (1994). (The table starts with column alpha = 0.) Here, the index alpha for the columns in Table 5 is the number of appendages to the core.
%C A045903 The table refers to the example described on pp. 1177-1179 of the paper and especially to Figure 5 (p. 1178). The entries refer to the number of nonisomorphic systems of catafusenes in this example (as shown in Figure 5, p. 1178).
%C A045903 The rows of Table 5 are indexed by the total number of hexagons in the appendages.
%C A045903 Therefore, a(n) = number of nonisomorphic systems of catefusenes in the example on pp. 1177-1179 of Cyvin et al. (1994) with alpha = 2 appendages to the core, where n = total number of hexagons in the appendages.
%C A045903 From Note 10 (p. 1180) in Cyvin et al. (1994), we see that (most probably) the number of hexagons a (= n in this sequence) does not include any hexagons in the core.
%C A045903 (End)
%H A045903 S. J. Cyvin, B. N. Cyvin, J. Brunvoll and E. Brendsdal, <a href="https://doi.org/10.1021/ci00021a026">Enumeration and Classification of Certain Polygonal Systems Representing Polycyclic Conjugated Hydrocarbons: Annelated Catafusenes</a>, Journal of Chemical Information and Modeling [formerly, J. Chem. Inform. Comput. Sci.], 34 (1994), pp. 1174-1180.
%H A045903 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Fusene.html">Fusene</a>.
%Y A045903 Cf. A121178.
%K A045903 nonn,more
%O A045903 0,3
%A A045903 _N. J. A. Sloane_
%E A045903 Name edited by _Petros Hadjicostas_, May 25 2019