Number of (n+1) X 9 0..2 arrays with all 2 X 2 subblock sums the same.

Terms

a(0) =35535a(1) =40041a(2) =47031a(3) =61125a(4) =85431a(5) =134853a(6) =227319a(7) =418461a(8) =799815a(9) =1612581a(10) =3338151a(11) =7206765a(12) =16031991a(13) =37247253a(14) =89664279a(15) =225444381a(16) =586169895a(17) =1579364421a(18) =4360148871a(19) =12326941005a(20) =35353745751a(21) =102812027253a(22) =301213506039