login
A192093
Number of tatami tilings of a 7 X n grid (with monomers allowed).
2
1, 21, 357, 406, 490, 584, 827, 1090, 1914, 3262, 6228, 10226, 17114, 25534, 41034, 61778, 102644, 163334, 278554, 446898, 747274, 1175494, 1926612, 3021594, 4960170, 7880334, 13028058, 20841466, 34355316, 54835150, 89785130
OFFSET
0,2
COMMENTS
A tatami tiling consists of dimers (1 X 2) and monomers (1 X 1) where no four meet at a point.
LINKS
A. Erickson, F. Ruskey, M. Schurch and J. Woodcock, Monomer-Dimer Tatami Tilings of Rectangular Regions, Electronic Journal of Combinatorics, 18(1) (2011) P109, 24 pages.
EXAMPLE
Here are some tatami tilings of the 7 X 3 grid:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
|_ _| |_| |_| | |_| |_|_ _| |_| | |_ _| |_| |_| |_| | |_ _| |_|
|_ _|_| |_| |_| | |_|_ _| |_| | |_| |_|_| |_| | | |_|_| |_|_| |
|_|_ _|_|_|_|_| |_|_ _|_|_|_|_| |_|_|_ _|_|_|_| |_|_ _|_|_ _|_|
CROSSREFS
Sequence in context: A300320 A271633 A184289 * A006105 A167032 A051564
KEYWORD
nonn
AUTHOR
Frank Ruskey and Yuji Yamauchi (eugene.uti(AT)gmail.com), Jul 14 2011
STATUS
approved