An Aztec diamond of order is the region obtained from four staircase shapes of height by gluing them together along the straight edges. It can therefore be defined as the union of unit squares in the plane whose edges lie on the lines of a square grid and whose centers satisfy
The first few are illustrated above. The number of squares in the Aztec diamond of order is , giving for , 2, ... the values 4, 12, 24, 40, 60, ... (OEIS A046092).
The number of domino tilings of an order Aztec diamond is , where is the triangular number (Elkies et al. 1992).
Note that Wassermann appears to use an incorrect definition of the Aztec diamond that is actually equivalent to that of a centered square number.