22524516domain: NAppears in sequencesNumber of nX3 0..2 arrays with every element neighboring horizontally or vertically both a 0 and a 1.at n=9A203537Number of 4Xn 0..1 arrays avoiding 0 0 1 and 0 1 1 horizontally and 0 0 1 and 1 1 0 vertically.at n=25A207404