|
Search: id:A098702
|
|
|
| A098702 |
|
Number of self-polar configurations of type (n_3). |
|
+0
5
|
|
| 0, 0, 0, 0, 0, 0, 1, 1, 3, 10, 25, 95, 365, 1432, 5799, 24092, 102413, 445363, 1991320
(list; graph; listen)
|
|
|
OFFSET
|
1,9
|
|
|
REFERENCES
|
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.
Pisanski, T.; Boben, M.; Marusic, D.; Orbanic, A.; and Graovac, A. 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
|
Cf. A001403, A023994.
Sequence in context: A095052 A131433 A110713 this_sequence A100001 A110158 A105660
Adjacent sequences: A098699 A098700 A098701 this_sequence A098703 A098704 A098705
|
|
KEYWORD
|
nonn,nice,hard
|
|
AUTHOR
|
N. J. A. Sloane (njas(AT)research.att.com), Nov 05 2004
|
|
EXTENSIONS
|
a(1)-a(18) from the Betten, Brinkmann and Pisanski article.
a(19) from the Pisanski et al. article.
|
|
|
Search completed in 0.002 seconds
|
