Number of (n+1) X 5 0..2 arrays with every 2 x 2 subblock summing to 4.

Terms

a(0) =309a(1) =447a(2) =741a(3) =1383a(4) =2829a(5) =6207a(6) =14421a(7) =35223a(8) =89949a(9) =238767a(10) =654501a(11) =1840263a(12) =5274669a(13) =15332127a(14) =45012981a(15) =133072503a(16) =395284989a(17) =1177990287a(18) =3518241861a(19) =10523267943a(20) =31506888909a(21) =94394837247a(22) =282932853141a(23) =848295242583