Number of (n+2) X 7 0..2 matrices with each 3 X 3 subblock idempotent.

Terms

a(0) =628a(1) =630a(2) =782a(3) =906a(4) =1202a(5) =1609a(6) =2091a(7) =2817a(8) =3895a(9) =5397a(10) =7564a(11) =10745a(12) =15361a(13) =22074a(14) =31895a(15) =46256a(16) =67251a(17) =97985a(18) =142995a(19) =208912a(20) =305472a(21) =446948a(22) =654244a(23) =958000a(24) =1403129a(25) =2055448a(26) =3011414a(27) =4412397a(28) =6465584a(29) =9474619