1/4 the number of (n+1) X 7 binary arrays with all 2 X 2 subblock sums the same.

Terms

a(0) =45a(1) =47a(2) =50a(3) =56a(4) =66a(5) =86a(6) =122a(7) =194a(8) =330a(9) =602a(10) =1130a(11) =2186a(12) =4266a(13) =8426a(14) =16682a(15) =33194a(16) =66090a(17) =131882a(18) =263210a(19) =525866a(20) =1050666a(21) =2100266a(22) =4198442a(23) =8394794a(24) =16785450a(25) =33566762a(26) =67125290a(27) =134242346a(28) =268468266a(29) =536920106