A156431 Number of nXn arrays of squares of integers, symmetric under 90 degree rotation, with all rows summing to 2.

1, 0, 2, 0, 12, 0, 90, 0, 810, 0, 8940, 0, 116760, 0, 1756860, 0, 29933820, 0, 569744280, 0, 11981526480, 0, 275893362360, 0, 6903968231160, 0, 186558764792400, 0, 5413973807642400