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%I #27 Nov 14 2024 10:07:45
%S 1,5,75,4632,1076492,963182263,3317770165381,43809083383524391,
%T 2209112327971366587064,424273291301040427702718109,
%U 309707064465485300360403957730000,857932019835933358500355409793382735115,9007779604382069542348587670082074125962102375
%N The number of placements of zero or more dominoes on the n X n grid where the number of vertical dominoes differs from the number of horizontal dominoes by at most 1.
%C The number of play positions of n X n Domineering. Domineering is a game in which players take turns placing dominoes on a grid, one player placing vertically and the other horizontally until the player to place cannot place a domino.
%H Bjorn Huntemann, Svenja Huntemann, and Neil A. McKay, <a href="http://www2.unb.ca/~nmckay/oeis/CountingDomineering.sagews">SageMath code for Counting Domineering Positions</a>
%H Svenja Huntemann and Neil A. McKay, <a href="https://arxiv.org/abs/1909.12419">Counting Domineering Positions</a>, arXiv:1909.12419 [math.CO], 2019.
%o (Sage) # See Bjorn Huntemann, Svenja Huntemann, Neil A. McKay link.
%Y Cf. A028420 (the number of placements of dominoes on an n X n grid).
%Y Cf. A330658, A332865.
%K nonn
%O 1,2
%A _Neil A. McKay_, Feb 20 2020
%E a(11)-a(13) from _Andrew Howroyd_, Feb 20 2020