551777domain: NAppears in sequencesNumber of zero-sum -n..n arrays of 5 elements with adjacent element differences also in -n..n.at n=20A202255Number of (n+1) X (7+1) 0..1 arrays with every 2 X 2 subblock ne-sw antidiagonal difference nondecreasing horizontally and nw+se diagonal sum nondecreasing vertically.at n=21A258553