|
| |
|
|
A075212
|
|
Number of polyhexes with n cells that tile the plane by translation or by 180-degree rotation (Conway criterion).
|
|
10
| |
|
|
1, 1, 3, 7, 21, 75, 257, 930, 3104, 9265, 21304, 81392, 139612, 427454, 1176912, 2491134, 4319362, 16243200, 21965930, 76738851, 158374741
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,3
|
|
|
REFERENCES
| Branko Gruenbaum and G. C. Shephard, Tilings and Patterns. W. H. Freeman, New York, 1987, Section 9.4.
|
|
|
LINKS
| Joseph Myers, Polyhex tiling
|
|
|
CROSSREFS
| Cf. A070766, A075207, A075208, A075209, A075210, A075211, A075213, A075214, A075215, A075203, A075221.
Sequence in context: A001576 A169587 A075211 * A173794 A049365 A031885
Adjacent sequences: A075209 A075210 A075211 * A075213 A075214 A075215
|
|
|
KEYWORD
| hard,nonn
|
|
|
AUTHOR
| Joseph Myers (jsm(AT)polyomino.org.uk), Sep 08 2002
|
|
|
EXTENSIONS
| More terms from Joseph Myers (jsm(AT)polyomino.org.uk), Nov 08 2003
a(20) and a(21) from Joseph Myers (jsm(AT)polyomino.org.uk), Nov 21 2010
|
| |
|
|
