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A219872 Number of tilings of a 9 X n rectangle using dominoes and straight (3 X 1) trominoes. 2
1, 5, 249, 17395, 862953, 53074167, 3105936858, 181382499259, 10750194262698, 631206895803116, 37197513508819191, 2191568660367709311, 129026759279686110418, 7600920859497795763717, 447657086066162084823497, 26365510156948695071183306 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..75

EXAMPLE

a(1) = 5, because there are 5 tilings of a 9 X 1 rectangle using dominoes and straight (3 X 1) trominoes:

._.    ._.    ._.    ._.    ._.

| |    | |    | |    | |    | |

| |    |_|    |_|    |_|    | |

|_|    | |    | |    | |    |_|

| |    |_|    |_|    | |    | |

| |    | |    | |    |_|    |_|

|_|    |_|    | |    | |    | |

| |    | |    |_|    |_|    |_|

| |    | |    | |    | |    | |

|_|    |_|    |_|    |_|    |_|

CROSSREFS

Column k=9 of A219866.

Sequence in context: A125533 A068727 A135095 * A282734 A115739 A142202

Adjacent sequences:  A219869 A219870 A219871 * A219873 A219874 A219875

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Nov 30 2012

STATUS

approved

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Last modified July 2 15:51 EDT 2020. Contains 335404 sequences. (Running on oeis4.)