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.

0, 0, 2, 5, 26, 101, 457, 1978, 8851, 39481, 178043

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• more

Comments

From Petros Hadjicostas, May 25 2019: (Start)

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.

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).

The rows of Table 5 are indexed by the total number of hexagons in the appendages.

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.

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.

(End)

Links

• S. J. Cyvin, B. N. Cyvin, J. Brunvoll and E. Brendsdal, Enumeration and Classification of Certain Polygonal Systems Representing Polycyclic Conjugated Hydrocarbons: Annelated Catafusenes, Journal of Chemical Information and Modeling [formerly, J. Chem. Inform. Comput. Sci.], 34 (1994), pp. 1174-1180.
• Eric Weisstein's World of Mathematics, Fusene.

Crossrefs

Cf. A121178.

Extensions

Name edited by Petros Hadjicostas, May 25 2019