A063804 Triangle T(n,k) (n >= 3, k = 1..n-2) read by rows, giving number of nonisomorphic oriented matroids with n points in n-k dimensions.
1, 1, 2, 1, 3, 4, 1, 4, 12, 17, 1, 5, 25, 206, 143, 1, 6, 50, 6029, 181472, 4890, 1, 7, 91, 508321
Offset: 3
Examples
Triangle begins: 1 1 2 1 3 4 1 4 12 17 1 5 25 206 143 1 6 50 6029 181472 4890 1 7 91 508321 unknown unknown 461053 ...
References
- Lukas Finschi, A Graph Theoretical Approach for Reconstruction and Generation of Oriented Matroids, A dissertation submitted to the Swiss Federal Institute of Technology, Zurich for the degree of Doctor of Mathematics, 2001.
- Fukuda, Komei; Miyata, Hiroyuki; Moriyama, Sonoko. Complete Enumeration of Small Realizable Oriented Matroids. Discrete Comput. Geom. 49 (2013), no. 2, 359--381. MR3017917. - From N. J. A. Sloane, Feb 16 2013
Links
- Lukas Finschi, Homepage of Oriented Matroids
- L. Finschi and K. Fukuda, Complete combinatorial generation of small point set configurations and hyperplane arrangements, pp. 97-100 in Abstracts 13th Canadian Conference on Computational Geometry (CCCG '01), Waterloo, Aug. 13-15, 2001.