T(n,k) = number of (n+2) X (k+2) binary matrices with every 3 X 3 block having exactly four 1's.

Terms

a(0) =126a(1) =336a(2) =336a(3) =906a(4) =746a(5) =906a(6) =2484a(7) =1684a(8) =1684a(9) =2484a(10) =7218a(11) =3942a(12) =3190a(13) =3942a(14) =7218a(15) =21024a(16) =10348a(17) =6360a(18) =6360a(19) =10348a(20) =21024a(21) =61398a(22) =27554a(23) =14974a(24) =10818a(25) =14974a(26) =27554a(27) =61398a(28) =182520a(29) =74784