A342554 Number of catafusenes with 2n hexagons and C symmetry.

0, 0, 1, 5, 22, 97, 408, 1752, 7535, 32895, 144816, 644058, 2886967, 13037352, 59248959, 270799903, 1243939278, 5740014143, 26594306442, 123668622726, 577003771681, 2700346810482, 12672753684799, 59625966523555, 281207237408728, 1329130156859362

Offset

0,4

Comments

Column C in Table 6 and Eq. (52) in Cyvin et al.

Links

Table of n, a(n) for n=0..25.

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.

Formula

a(n) = (1/4) * (A002212(n+1) - A002212(n) - A039658(n)) - (1/2) * (A055879(n) + A002212(n/2) - A055879(n/2)) where sequences are assumed 0 for non-integer arguments.

Crossrefs

Cf. A045906, A045907, A045908, A045909, A342570.

Sequence in context: A200676 A297333 A129158 * A129164 A123347 A087439

Adjacent sequences: A342551 A342552 A342553 * A342555 A342556 A342557

Keyword

nonn

Author

Sean A. Irvine, Mar 27 2021

Status

approved