Number of (n+1) X 7 0..2 matrices with each 2 X 2 subblock idempotent.

Terms

a(0) =189a(1) =300a(2) =398a(3) =573a(4) =793a(5) =1126a(6) =1608a(7) =2343a(8) =3471a(9) =5236a(10) =8022a(11) =12457a(12) =19553a(13) =30950a(14) =49300a(15) =78895a(16) =126679a(17) =203888a(18) =328702a(19) =530537a(20) =856989a(21) =1385070a(22) =2239388a(23) =3621563a(24) =5857823a(25) =9476016a(26) =15330218a(27) =24802353a(28) =40128421a(29) =64926346