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A058717 Triangle T(n,k) giving number of nonisomorphic loopless matroids of rank k on n labeled points (n >= 1, 1<=k<=n). 1
1, 1, 1, 1, 2, 1, 1, 4, 3, 1, 1, 6, 9, 4, 1, 1, 10, 25, 18, 5, 1, 1, 14, 70, 85, 31, 6, 1, 1, 21, 217, 832, 288, 51, 7, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET
1,5
LINKS
W. M. B. Dukes, Tables of matroids
W. M. B. Dukes, Counting and Probability in Matroid Theory, Ph.D. Thesis, Trinity College, Dublin, 2000.
EXAMPLE
1;
1, 1;
1, 2, 1;
1, 4, 3, 1;
1, 6, 9, 4, 1;
1, 10, 25, 18, 5, 1;
1, 14, 70, 85, 31, 6, 1;
1, 21, 217, 832, 288, 51, 7, 1;
...
CROSSREFS
Cf. A058716 (same except for border), A058710, A058711.
Row sums give A058718. Diagonals give A000065, A058719.
Sequence in context: A347699 A055080 A034367 * A034371 A318951 A101321
KEYWORD
nonn,tabl,nice
AUTHOR
N. J. A. Sloane, Dec 31 2000
EXTENSIONS
Corrected and extended by Jean-François Alcover, Oct 21 2013
Reverted to original data by Jean-François Alcover, Aug 17 2022
STATUS
approved

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Last modified March 19 03:33 EDT 2024. Contains 370952 sequences. (Running on oeis4.)