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

3,10

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).)

Links

Table of n, a(n) for n=3..27.

Example

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
...

Crossrefs

Rightmost diagonal is A018242.

Different from A063851.

Sequence in context: A127707 A113196 A037291 * A063851 A124777 A352834

Adjacent sequences: A222314 A222315 A222316 * A222318 A222319 A222320

Keyword

nonn,tabl,more

Author

N. J. A. Sloane, Feb 16 2013

Status

approved