626434domain: NAppears in sequencesNumber of (n+1) X (2+1) 0..2 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 2 (constant-stress 1 X 1 tilings).at n=12A234260G.f. satisfies: A(x) = (4 + A(x)^4) / (5-x).at n=6A244856