Number of polyiamonds with n cells that tile the plane by translation or by 180-degree rotation (Conway criterion).

A075221

Number of polyiamonds with n cells that tile the plane by translation or by 180-degree rotation (Conway criterion).

Terms

    a(0) =1a(1) =1a(2) =1a(3) =3a(4) =4a(5) =12a(6) =21a(7) =56a(8) =111a(9) =262a(10) =462a(11) =1453a(12) =1875a(13) =4734a(14) =9410a(15) =20603a(16) =24034a(17) =79352a(18) =79925a(19) =273731a(20) =358096a(21) =669640a(22) =796571a(23) =3342349a(24) =2980476a(25) =6387513a(26) =10167660a(27) =24999509a(28) =21477012a(29) =87978317

External references