The number of tilings of an 8 X (3n) floor with 2 X 3 hexominoes.

Terms

a(0) =1a(1) =1a(2) =4a(3) =11a(4) =33a(5) =96a(6) =281a(7) =821a(8) =2400a(9) =7015a(10) =20505a(11) =59936a(12) =175193a(13) =512089a(14) =1496836a(15) =4375251a(16) =12788857a(17) =37381824a(18) =109267057a(19) =319387565a(20) =933569728a(21) =2728823951a(22) =7976351345a(23) =23314871872a(24) =68149361393