Number of tilings of a 3 X n strip with dominos and U-shaped pentominos.

Terms

a(0) =1a(1) =0a(2) =3a(3) =0a(4) =12a(5) =2a(6) =50a(7) =16a(8) =210a(9) =100a(10) =888a(11) =558a(12) =3778a(13) =2926a(14) =16164a(15) =14758a(16) =69520a(17) =72504a(18) =300458a(19) =349586a(20) =1304390a(21) =1662320a(22) =5686114a(23) =7821308a(24) =24879632a(25) =36497742a(26) =109227706a(27) =169207550a(28) =480982532a(29) =780370350