Number of polyominoes with n cells that tile the plane isohedrally.

Terms

a(0) =1a(1) =1a(2) =2a(3) =5a(4) =12a(5) =35a(6) =104a(7) =342a(8) =1041a(9) =3026a(10) =6512a(11) =23227a(12) =38238a(13) =108204a(14) =278426a(15) =544635a(16) =825654a(17) =3049903a(18) =3375582a(19) =12108377a(20) =21899125a(21) =36960289a(22) =53317222a(23) =220706640a(24) =271264826