%I #12 Jun 30 2023 07:46:39

%S 1,4,14,40,120,320,946,2496,7418,19616

%N Number of states with reflective symmetry arising in matrix method for enumerating Hamiltonian cycles on 2n X 2n grid.

%H Ed Wynn, <a href="http://arxiv.org/abs/1402.0545">Enumeration of nonisomorphic Hamiltonian cycles on square grid graphs</a>, arXiv preprint arXiv:1402.0545 [math.CO], 2014.

%Y Cf. A003763, A143246, A209077, A222065, A238115, A238116, A238118.

%K nonn,more

%O 1,2

%A _N. J. A. Sloane_, Mar 05 2014