A222317 Triangle read by rows: T(n,k) (n>=3, 1<=k<=n-2) = number of uniform realizable oriented matroids with n elements and rank n-k+1.
1, 1, 1, 1, 1, 1, 1, 1, 1, 4, 1, 1, 1, 11, 11, 1, 1, 1, 135, 2604, 135, 1, 1, 1, 4381
Offset: 3
Examples
Triangle begins 1 1 1 1 1 1 1 1 1 4 1 1 1 11 11 1 1 1 135 2604 135 1 1 1 4381 unknown unknown unknown ...
References
- Fukuda, Komei; Miyata, Hiroyuki; Moriyama, Sonoko. Complete Enumeration of Small Realizable Oriented Matroids. Discrete Comput. Geom. 49 (2013), no. 2, 359--381. MR3017917. (The (4) in the r=4 row of Table 2 should probably be (1).)