%I M0330 N0125 #32 Dec 28 2016 20:04:14
%S 1,0,0,2,2,4,8,4,16,12,48,80,136,420,1240,3000,8152,18104,44184,
%T 144620,375664,1250692,3581240,11675080,34132592,115718268,320403024,
%U 1250901440,3600075088,14589438024,43266334696,181254386312
%N Number of point symmetric solutions to non-attacking queens problem on n X n board.
%D N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%D R. J. Walker, An enumerative technique for a class of combinatorial problems, pp. 91-94 of Proc. Sympos. Applied Math., vol. 10, Amer. Math. Soc., 1960.
%H W. Schubert, <a href="/A032522/b032522.txt">Table of n, a(n) for n = 1..40</a>
%H Tricia M. Brown, <a href="http://dx.doi.org/10.5642/jhummath.201601.08">Kaleidoscopes, Chessboards, and Symmetry</a>, Journal of Humanistic Mathematics, Volume 6 Issue 1 ( January 2016), pages 110-126.
%H Gheorghe Coserea, <a href="/A032522/a032522_2.txt">Solutions for n=10</a>.
%H Gheorghe Coserea, <a href="/A032522/a032522_3.txt">Solutions for n=11</a>.
%H Gheorghe Coserea, <a href="/A032522/a032522_1.mzn.txt">MiniZinc model for generating solutions</a>.
%H W. Schubert, <a href="http://web.archive.org/web/20130708134012/http://m29s20.vlinux.de/~wschub/nqueen.html">N-Queens page</a>
%H M. Szabo, <a href="http://www.nexus.hu/mikk/queen/index.html">Non-attacking Queens Problem Page</a>
%Y Cf. A002562, A033148, A037224, A037223.
%K nonn,nice,hard
%O 1,4
%A Miklos SZABO (mike(AT)ludens.elte.hu)
%E More terms for n = 33..36 from _W. Schubert_, Jul 31 2009