Number of polyhexes with n cells that tile the plane by translation but not by 180-degree rotation (Conway criterion).

A075208

Number of polyhexes with n cells that tile the plane by translation but not by 180-degree rotation (Conway criterion).

Terms

    a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =1a(7) =1a(8) =14a(9) =30a(10) =88a(11) =929a(12) =989a(13) =3859a(14) =16557a(15) =35017a(16) =46506a(17) =256901a(18) =256721a(19) =1286189a(20) =2306003

External references