Number of tilings of a 4 X n rectangle using tetrominoes of shapes L, T, Z.

Terms

a(0) =1a(1) =0a(2) =2a(3) =10a(4) =24a(5) =70a(6) =276a(7) =820a(8) =2616a(9) =8702a(10) =27902a(11) =89500a(12) =291050a(13) =939222a(14) =3029950a(15) =9798606a(16) =31657182a(17) =102237766a(18) =330356240a(19) =1067310022a(20) =3447911968a(21) =11139391996a(22) =35988377472a(23) =116265759012a(24) =375619824338