

A058731


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


3



0, 0, 0, 1, 2, 4, 9, 23, 68, 383, 5249, 232928, 28872972
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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, GianCarlo; On the foundations of combinatorial theory. II. Combinatorial geometries, Studies in Appl. Math. 49 1970 109133. [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



