Number of 4Xn 0..1 arrays avoiding 0 0 1 and 0 1 1 horizontally and 0 0 1 and 1 1 0 vertically.

Terms

a(0) =8a(1) =64a(2) =216a(3) =729a(4) =1782a(5) =4356a(6) =8910a(7) =18225a(8) =33210a(9) =60516a(10) =101598a(11) =170569a(12) =269276a(13) =425104a(14) =639612a(15) =962361a(16) =1393020a(17) =2016400a(18) =2827220a(19) =3964081a(20) =5411538a(21) =7387524a(22) =9858186a(23) =13155129a(24) =17213742a(25) =22524516a(26) =28974330a(27) =37271025a(28) =47228280a(29) =59845696