Number of tilings of a 6 X n rectangle with right trominoes.

Terms

a(0) =1a(1) =0a(2) =4a(3) =8a(4) =18a(5) =72a(6) =162a(7) =520a(8) =1514a(9) =4312a(10) =13242a(11) =39088a(12) =118586a(13) =361712a(14) =1103946a(15) =3403624a(16) =10513130a(17) =32614696a(18) =101530170a(19) =316770752a(20) =990771834a(21) =3104283168a(22) =9741133578a(23) =30606719000a(24) =96263812906a(25) =303028237848a(26) =954563802106