|
| |
|
|
A084477
|
|
Number of fault-free tilings of (4 X 3n) rectangle with right tromino.
|
|
4
| |
|
|
4, 2, 8, 48, 288, 1728, 10368, 62208, 373248, 2239488, 13436928, 80621568, 483729408, 2902376448, 17414258688, 104485552128, 626913312768, 3761479876608, 22568879259648, 135413275557888, 812479653347328
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
COMMENTS
| Fault-free tilings are those where the only straight interface is at the left and right end. Thus a(n) <= A046984(n).
For n>1, a(n) = 2*A067411(n-2).
|
|
|
LINKS
| C. Moore, [math/9905012] Some Polyomino Tilings of the Plane
M. Aanjaneya and S. P. Pal, Faultfree tromino tilings of rectangles
|
|
|
FORMULA
| G.f.: 2z(2-11z-2z^2) / (1-6z). a(n) = 8 * 6^(n-3), for n>2.
|
|
|
CROSSREFS
| Cf. A084478, A084479, A084480, A084481.
Sequence in context: A204449 A172393 A040174 * A046589 A072562 A190477
Adjacent sequences: A084474 A084475 A084476 * A084478 A084479 A084480
|
|
|
KEYWORD
| nonn,easy
|
|
|
AUTHOR
| Ralf Stephan (ralf(AT)ark.in-berlin.de), May 27 2003
|
| |
|
|
