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A192091 Number of tatami tilings of a 5 by n grid (with monomers allowed). 3
1, 8, 68, 90, 126, 178, 325, 584, 1165, 2030, 3619, 6080, 10987, 19362, 35477, 62360, 111837, 195614, 350707, 619568, 1112315, 1967090, 3514597, 6214984, 11093549, 19664558, 35090115, 62247552, 110934699, 196859394, 350650261 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

A tatami tiling consists of dimers (1x2) and monomers (1x1) where no four meet at a point.

LINKS

Table of n, a(n) for n=0..30.

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 5 by 3 grid:

    _ _ _ _ _   _ _ _ _ _   _ _ _ _ _   _ _ _ _ _

   |_ _| |_| | |_| |_|_ _| | |_ _| |_| |_| | |_ _|

   |_ _|_| |_| | |_|_ _| | |_| |_|_| | | |_|_| | |

   |_|_ _|_|_| |_|_ _|_|_| |_|_|_ _|_| |_|_ _|_|_|

CROSSREFS

Cf. A192090, A192092, A033508 (without tatami condition). Row sums of A272474.

Sequence in context: A000434 A304073 A250258 * A050841 A208947 A296670

Adjacent sequences:  A192088 A192089 A192090 * A192092 A192093 A192094

KEYWORD

nonn

AUTHOR

Frank Ruskey and Yuji Yamauchi (eugene.uti(AT)gmail.com), Jul 07 2011

STATUS

approved

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Last modified December 18 16:37 EST 2018. Contains 318229 sequences. (Running on oeis4.)