A192093 Number of tatami tilings of a 7 X n grid (with monomers allowed).

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

Author

Frank Ruskey and Yuji Yamauchi (eugene.uti(AT)gmail.com), Jul 14 2011

Keywords

• nonn

Comments

A tatami tiling consists of dimers (1 X 2) and monomers (1 X 1) where no four meet at a point.

Examples

			Here are some tatami tilings of the 7 X 3 grid:
    _ _ _ _ _ _ _   _ _ _ _ _ _ _   _ _ _ _ _ _ _   _ _ _ _ _ _ _
   |_ _| |_| |_| | |_| |_|_ _| |_| | |_ _| |_| |_| |_| | |_ _| |_|
   |_ _|_| |_| |_| | |_|_ _| |_| | |_| |_|_| |_| | | |_|_| |_|_| |
   |_|_ _|_|_|_|_| |_|_ _|_|_|_|_| |_|_|_ _|_|_|_| |_|_ _|_|_ _|_|
		

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.

Crossrefs

Cf. A192092, A192094.