Number of tilings of a 5 X n rectangle using n pentominoes of shapes F, I, L.

Terms

a(0) =1a(1) =1a(2) =3a(3) =5a(4) =13a(5) =50a(6) =133a(7) =360a(8) =875a(9) =2254a(10) =6336a(11) =17331a(12) =47199a(13) =124476a(14) =330344a(15) =889454a(16) =2400961a(17) =6485476a(18) =17392906a(19) =46616158a(20) =125153478a(21) =336529923a(22) =905611165a(23) =2434088873a(24) =6539233985a(25) =17567977887a(26) =47214493386a(27) =126927551197a(28) =341177175540a(29) =916960655233