2500555domain: NAppears in sequencesNumber of defective 4-colorings of an n X 3 0..3 array connected horizontally, vertically, diagonally and antidiagonally with exactly two mistakes, and colors introduced in row-major 0..3 order.at n=11A229750G.f. satisfies: A(x) = 1 + x*A(x) * ( d/dx x*A(x)^4 ).at n=6A317354