A363771 Number of graphs (with n vertices) admitting a strictly matched involution.

1, 1, 1, 2, 4, 9, 21, 65, 240, 1128, 6764, 53971

Offset

0,4

Links

Table of n, a(n) for n=0..11.

S. D. Andres, F. Dross, M. A. Huggan, F. Mc Inerney, and R. J. Nowakowski, The complexity of two colouring games, Algorithmica, 85 (2023), 1067-1090.

S. D. Andres, M. Huggan, F. Mc Inerney, and R. J. Nowakowski, The orthogonal colouring game, Theor. Comput. Sci., 795 (2019), 312-325.

S. D. Andres, M. Huggan, F. Mc Inerney, and R. J. Nowakowski, Corrigendum to "The orthogonal colouring game" [Theor. Comput. Sci. 795 (2019) 312-325], Theor. Comput. Sci., 842 (2020), 133-135.

Example

For n=0 the a(0)=1 solution is the empty graph K0.
For n=1 the a(1)=1 solution is the complete graph K1.
For n=2 the a(2)=1 solution is the complete graph K2.
For n=3 the a(3)=2 solutions are the complete graph K3 and the union of K1 and K2.
For n=4 the a(4)=4 solutions are the complete graph K4, the 4-cycle C4, the paw (3-pan), and the 2K2 (union of two K2).

Crossrefs

Cf. A363772.

Sequence in context: A148076 A217976 A156801 * A057580 A129875 A055094

Adjacent sequences: A363768 A363769 A363770 * A363772 A363773 A363774

Keyword

nonn,hard,more

Author

Stephan Dominique Andres, Jun 21 2023

Status

approved