Number of tribone tilings of an n-triangle.

Terms

a(0) =1a(1) =0a(2) =1a(3) =0a(4) =0a(5) =0a(6) =0a(7) =0a(8) =0a(9) =2a(10) =0a(11) =8a(12) =12a(13) =0a(14) =72a(15) =0a(16) =0a(17) =0a(18) =0a(19) =0a(20) =0a(21) =185328a(22) =0a(23) =4736520a(24) =21617456a(25) =0a(26) =912370744a(27) =0a(28) =0a(29) =0