%I #5 May 14 2019 11:01:06
%S 0,4,756,11197440,25328684620800,14303252551164700262400,
%T 2979637719108524426779310260224000
%N Number of (undirected) Hamiltonian paths in the n X n rook graph.
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/HamiltonianPath.html">Hamiltonian Path</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/RookGraph.html">Rook Graph</a>
%F a(n) = A096970(n)/2.
%Y Cf. A096970.
%K nonn,hard,more
%O 1,2
%A _Eric W. Weisstein_, May 14 2019