Number of polyhexes with n cells that tile the plane by translation or by 180-degree rotation (Conway criterion).
1, 1, 3, 7, 21, 75, 257, 930, 3104, 9265, 21304, 81392, 139612, 427454, 1176912
1 seqfan posts
Tue Feb 10 17:40:26 CET 2009 [seqfan] A001576