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A219874

Number of tilings of an n X n square using dominoes and straight (3 X 1) trominoes.

1, 0, 2, 14, 184, 9612, 1143834, 354859954, 295743829064, 631206895803116, 3541054185616706122, 51821077154605344550820, 1976225122734369352127065686

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OFFSET

0,3

LINKS

EXAMPLE

a(3) = 14, because there are 14 tilings of a 3 X 3 square using dominoes and straight (3 X 1) trominoes:

._____. ._____. ._____. ._____. .___._. .___._. .___._.

| | | | | | | | | |___| | |___| | | | | |___| | |___| |

| | | | | |_|_| | |___| | | | | |_|_| | |___| | | | | |

|_|_|_| |_|___| |_|___| |_|_|_| |___|_| |___|_| |_|_|_|

._____. ._____. ._____. ._____. ._____. ._____. ._____.

|_____| |_____| |_____| |_____| | |___| | | | | |___| |

|_____| | |___| | | | | |___| | |_|___| |_|_|_| |___|_|

|_____| |_|___| |_|_|_| |___|_| |_____| |_____| |_____| .

CROSSREFS

Main diagonal of A219866.

KEYWORD

nonn,more

AUTHOR

EXTENSIONS

a(12) from Alois P. Heinz, Sep 30 2014

STATUS

approved