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A098702 Number of self-polar configurations of type (n_3). 4
0, 0, 0, 0, 0, 0, 1, 1, 3, 10, 25, 95, 365, 1432, 5799, 24092, 102413, 445363, 1991320 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,9
LINKS
A. Betten, G. Brinkmann and T. Pisanski, Counting symmetric configurations v_3, Discrete Appl. Math., 99 (2000), 331-338.
M. Boben et al., Small triangle-free configurations of points and lines, Discrete Comput. Geom., 35 (2006), 405-427.
T. Pisanski, M. Boben, D. Marušic, A. Orbanic, A. Graovac, The 10-cages and derived configurations, Discrete Math. 275 (2004), 265-276.
EXAMPLE
Example: the Fano plane is the only 7_3 configuration and it is self-polar.
CROSSREFS
Sequence in context: A196984 A131433 A110713 * A100001 A227937 A299754
KEYWORD
nonn,nice,hard
AUTHOR
N. J. A. Sloane, Nov 05 2004
EXTENSIONS
a(1)-a(18) from the Betten, Brinkmann and Pisanski article.
a(19) from the Pisanski et al. article.
STATUS
approved

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Last modified March 28 05:39 EDT 2024. Contains 371235 sequences. (Running on oeis4.)