Number of tilings of a 4 X n rectangle using integer-sided rectangular tiles of area 4.

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =9a(5) =16a(6) =35a(7) =65a(8) =143a(9) =281a(10) =590a(11) =1174a(12) =2440a(13) =4925a(14) =10142a(15) =20563a(16) =42178a(17) =85819a(18) =175632a(19) =357875a(20) =731536a(21) =1491966a(22) =3047879a(23) =6218844a(24) =12699982a(25) =25919176a(26) =52922491a(27) =108022099a(28) =220541999a(29) =450186874