164036domain: NAppears in sequencesNumber of (n,2)-polyominoes.at n=8A286194Length of n-th iterate of the mapping 00->0010, 01->100, 10->001 in A289165.at n=21A289168Array read by diagonals downwards: A(n,k) for n>=2 and k>=0 is the number of (n,k)-polyominoes.at n=52A381030