|
%I #8 May 31 2018 21:38:06
%S 0,0,0,0,0,0,1,1,3,10,25,95,365,1432,5799,24092,102413,445363,1991320
%N Number of self-polar configurations of type (n_3).
%H A. Betten, G. Brinkmann and T. Pisanski, <a href="https://doi.org/10.1016/S0166-218X(99)00143-2">Counting symmetric configurations v_3</a>, Discrete Appl. Math., 99 (2000), 331-338.
%H M. Boben et al., <a href="https://doi.org/10.1007/s00454-005-1224-9">Small triangle-free configurations of points and lines</a>, Discrete Comput. Geom., 35 (2006), 405-427.
%H T. Pisanski, M. Boben, D. MaruĊĦic, A. Orbanic, A. Graovac, <a href="https://doi.org/10.1016/S0012-365X(03)00110-9">The 10-cages and derived configurations</a>, Discrete Math. 275 (2004), 265-276.
%e Example: the Fano plane is the only 7_3 configuration and it is self-polar.
%Y Cf. A001403, A023994.
%K nonn,nice,hard
%O 1,9
%A _N. J. A. Sloane_, Nov 05 2004
%E a(1)-a(18) from the Betten, Brinkmann and Pisanski article.
%E a(19) from the Pisanski et al. article.
|
