Number of tilings of a 5 X n rectangle using straight (3 X 1) trominoes and 2 X 2 tiles.

Terms

a(0) =1a(1) =0a(2) =2a(3) =4a(4) =8a(5) =28a(6) =65a(7) =170a(8) =456a(9) =1177a(10) =3068a(11) =8016a(12) =21028a(13) =54696a(14) =142908a(15) =374527a(16) =976022a(17) =2551162a(18) =6674999a(19) =17422250a(20) =45536000a(21) =119053392a(22) =310969076a(23) =812695944a(24) =2124175469a(25) =5550025712a(26) =14503987368a(27) =37905500955a(28) =99050326532a(29) =258846292750