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%I #10 Jun 30 2023 12:17:49
%S 1,4,44,2828,564468,754425400,3079904455096,88444819222239178,
%T 7685637690960745082050,4793315937811919497089287562
%N Number of Hamiltonian cycles on 2n X 2n grid with at least the symmetry of reflection in an axis.
%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.
%K nonn,more
%O 1,2
%A _N. J. A. Sloane_, Mar 05 2014