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

Terms

a(0) =1a(1) =0a(2) =3a(3) =12a(4) =23a(5) =94a(6) =289a(7) =842a(8) =2771a(9) =8510a(10) =26411a(11) =83122a(12) =258199a(13) =805914a(14) =2517287a(15) =7846960a(16) =24490017a(17) =76416244a(18) =238387767a(19) =743840496a(20) =2320800841a(21) =7240890040a(22) =22592311143a(23) =70488834118a(24) =219928631821a(25) =686190651342