A058731 Number of nonisomorphic simple matroids of rank 3 on n unlabeled points.

0, 0, 0, 1, 2, 4, 9, 23, 68, 383, 5249, 232928, 28872972

Offset

0,5

Links

Table of n, a(n) for n=0..12.

Mohamed Barakat, Reimer Behrends, Christopher Jefferson, Lukas Kühne, Martin Leuner, On the generation of rank 3 simple matroids with an application to Terao's freeness conjecture, arXiv:1907.01073 [math.CO], 2019.

Crapo, Henry H.; Rota, Gian-Carlo; On the foundations of combinatorial theory. II. Combinatorial geometries, Studies in Appl. Math. 49 1970 109-133. [Annotated scanned copy of pages 126 and 127 only]

W. M. B. Dukes, Tables of matroids

W. M. B. Dukes, Counting and Probability in Matroid Theory, Ph.D. Thesis, Trinity College, Dublin, 2000.

Index entries for sequences related to matroids

Crossrefs

Equals A001200 - 1 (see that entry for further information).

A diagonal of A058730.

Sequence in context: A089844 A113997 A125789 * A291981 A326908 A229048

Adjacent sequences: A058728 A058729 A058730 * A058732 A058733 A058734

Keyword

nonn,nice,more

Author

N. J. A. Sloane, Dec 31 2000; May 28 2006

Extensions

Definition corrected by Gordon Royle, Feb 13 2007

Status

approved