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Number of catafusenes with 2n hexagons and D_{2h}(a) symmetry.
2

%I #12 Mar 27 2021 23:50:48

%S 0,1,1,3,4,9,13,29,46,101,167,375,644,1461,2563,5899,10534,24469,

%T 44237,103643,189302,446381,821905,1948853,3612868,8605289,16044151,

%U 38362199,71877226,172423769,324440379,780496109,1474118424,3554991269,6736507309,16281079899

%N Number of catafusenes with 2n hexagons and D_{2h}(a) symmetry.

%C Column D_{2h}(a) in Table 6 and Eq. (51) in Cyvin et al.

%H 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.

%F a(n) = A055879(n) + (1/2) * (A039658(n) - A055879(n/2)) where A055879 is 0 for non-integer arguments.

%Y Cf. A045906, A045907, A045908, A045909, A342554.

%K nonn

%O 0,4

%A _Sean A. Irvine_, Mar 27 2021