Number of polyhexes with n cells that tile the plane.

Terms

a(0) =1a(1) =1a(2) =3a(3) =7a(4) =22a(5) =77a(6) =294a(7) =1054a(8) =3788a(9) =11326a(10) =24790a(11) =103641a(12) =164559a(13) =532510a(14) =1574252a(15) =2939898a(16) =4761009a(17) =21048218a(18) =24306306a(19) =95707819a(20) =205176450