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A219973 Number of tilings of a 9 X n rectangle using straight (3 X 1) trominoes and 2 X 2 tiles. 2

%I

%S 1,1,5,35,165,1177,9407,55657,372429,2766100,17671945,118674685,

%T 837152398,5531816082,37328192350,257252634864,1725117502706,

%U 11666552132346,79612474584518,537157628862720,3636277021289585,24711657036469040,167150255133278869

%N Number of tilings of a 9 X n rectangle using straight (3 X 1) trominoes and 2 X 2 tiles.

%H Alois P. Heinz, <a href="/A219973/b219973.txt">Table of n, a(n) for n = 0..50</a>

%e a(2) = 5, because there are 5 tilings of a 9 X 2 rectangle using straight (3 X 1) trominoes and 2 X 2 tiles:

%e .___. .___. .___. .___. .___.

%e | | | | | | | | | | | |

%e | | | | | | |___| |___| |___|

%e |_|_| |_|_| | | | | | | |

%e | | | | | | | | |___| |___|

%e | | | |___| |_|_| | | | | |

%e |_|_| | | | | | | | |___|

%e | | | |___| |___| |_|_| | | |

%e | | | | | | | | | | | |

%e |_|_| |___| |___| |___| |_|_|

%Y Column k=9 of A219967.

%K nonn

%O 0,3

%A _Alois P. Heinz_, Dec 02 2012

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Last modified July 1 04:13 EDT 2022. Contains 354951 sequences. (Running on oeis4.)