18059375domain: NAppears in sequencesPisot sequences E(5,7), P(5,7).at n=40A020711Pisot sequences E(7,10), P(7,10).at n=39A020721Number of nX2 0..1 arrays with every element unequal to 0, 1 or 2 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.at n=21A317759