221692domain: NAppears in sequencesNumber of (n+1) X (3+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=20A258549Number of edges in an equal-armed cross with arms of length n (see Comments in A331456 for definition).at n=10A333036