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Number of tilings of an 8 X n rectangle using straight (3 X 1) trominoes and 2 X 2 tiles.
2

%I #9 Nov 28 2016 00:37:44

%S 1,0,4,19,70,456,2530,12343,66653,372429,1910822,10162059,55583124,

%T 291195073,1550518247,8363883923,44269140576,235940940726,

%U 1264437357202,6723179849519,35846240541026,191571690239220,1020536749613565,5442225134864810,29051213879574079

%N Number of tilings of an 8 X n rectangle using straight (3 X 1) trominoes and 2 X 2 tiles.

%H Alois P. Heinz, <a href="/A219972/b219972.txt">Table of n, a(n) for n = 0..100</a>

%e a(2) = 4, because there are 4 tilings of an 8 X 2 rectangle using straight (3 X 1) trominoes and 2 X 2 tiles:

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

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

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

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

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

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

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

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

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

%Y Column k=8 of A219967.

%K nonn

%O 0,3

%A _Alois P. Heinz_, Dec 02 2012