T(n,k)=Number of (n+2)X(k+2) 0..1 matrices with each 3X3 subblock having the same population.

Terms

a(0) =512a(1) =1280a(2) =1280a(3) =3200a(4) =2688a(5) =3200a(6) =8000a(7) =5696a(8) =5696a(9) =8000a(10) =22400a(11) =12320a(12) =10304a(13) =12320a(14) =22400a(15) =62720a(16) =31232a(17) =19328a(18) =19328a(19) =31232a(20) =62720a(21) =175616a(22) =80160a(23) =44096a(24) =31616a(25) =44096a(26) =80160a(27) =175616a(28) =514304a(29) =209216