Number of (n+3) X 6 0..2 matrices with each 4 X 4 subblock idempotent.

Terms

a(0) =2471a(1) =2493a(2) =3092a(3) =3502a(4) =3775a(5) =4868a(6) =6540a(7) =8551a(8) =10761a(9) =13991a(10) =18817a(11) =25579a(12) =34473a(13) =46520a(14) =63313a(15) =86789a(16) =119077a(17) =163331a(18) =224294a(19) =308650a(20) =425208a(21) =585935a(22) =807537a(23) =1113408a(24) =1535747a(25) =2118724a(26) =2923211a(27) =4033478a(28) =5565990a(29) =7681386