A024311 Catacondensed simply-connected monopentapolyhexes.

0, 0, 1, 7, 30, 132, 559, 2416, 10483, 46072, 204155, 912779, 4110644, 18636572, 84985825, 389586145, 1794268460, 8298524480, 38527095859, 179487051589, 838820171722, 3931498431052, 18475618863389, 87036535974062, 410947146076475

Offset

1,4

Links

Table of n, a(n) for n=1..25.

S. J. Cyvin, B. N. Cyvin, J. Brunvoll, Zhang Fuji, Guo Xiaofeng, R. Tosic, Graph-theoretical studies on fluoranthenoids and fluorenoids: enumeration of some catacondensed systems, J. Molec. Struct. (Theochem), 285 (1993), 179-185.

Formula

a(n) = (1/2) * (A002212(n) - 2*A002212(n - 1) - A055879(n)). - Sean A. Irvine, Jun 26 2019

G.f.: (6*x^3 - 12*x^2 + 6*x + (2*x^2-3*x+1) * sqrt(1-x) * sqrt(1-5*x) - sqrt(1-x^2) * sqrt(1-5*x^2)) / (4*x*(x-1)). - Sean A. Irvine, Jun 26 2019

Crossrefs

Cf. A007317, A046697.

Sequence in context: A171472 A369201 A220720 * A210100 A297080 A375308

Adjacent sequences: A024308 A024309 A024310 * A024312 A024313 A024314

Keyword

nonn

Author

N. J. A. Sloane, May 03 2000

Extensions

More terms from Sean A. Irvine, Jun 26 2019

Status

approved