85231domain: NAppears in sequencesNumber of nondecreasing integer sequences of length 21 with sum zero and sum of absolute values 2n.at n=16A158155Number of nX3 0..1 arrays with every element equal to 0, 2, 3, 5 or 6 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.at n=12A301325