33565612800domain: NAppears in sequencesNumber of Eulerian cycles in a lattice graph bounded by the eight equations x+y=-2n, x+y=2n, x-y=-2n, x-y=2n, x=1-2n, x=2n-1, y=1-2n, and y=2n-1 (Aztec Diamond graph).at n=3A253107