A000948 Number of free nonplanar polyenoids with n nodes and symmetry point group C_s.

0, 3, 20, 99, 450, 1896, 7771, 30895, 121144, 468409, 1796584, 6841014, 25925062

Offset

7,2

Links

Table of n, a(n) for n=7..19.

S. J. Cyvin, J. Brunvoll, E. Brendsdal, B. N. Cyvin and E. K. Lloyd, Enumeration of polyene hydrocarbons: a complete mathematical solution, J. Chem. Inf. Comput. Sci., 35 (1995) 743-751.

S. J. Cyvin, J. Brunvoll, E. Brendsdal, B. N. Cyvin and E. K. Lloyd, Enumeration of polyene hydrocarbons: a complete mathematical solution, J. Chem. Inf. Comput. Sci., 35 (1995) 743-751. [Annotated scanned copy]

Formula

a(n) = A000131(n+2) - A000941(n). - Sean A. Irvine, Oct 15 2015

Crossrefs

Sequence in context: A305203 A379745 A246150 * A074831 A203357 A304494

Adjacent sequences: A000945 A000946 A000947 * A000949 A000950 A000951

Keyword

nonn,more

Author

E. K. Lloyd (E.K.Lloyd(AT)soton.ac.uk)

Extensions

a(16)-a(19) and title improved by Sean A. Irvine, Oct 16 2015

Status

approved