%I #28 Jul 26 2023 19:09:22

%S 1,0,2,8,380,21272,5350806,3238675344,6652506271144,38896105985522272,

%T 711716770252031164458,38776997923112110535353528,

%U 6460929292946758939597712150496,3245656750963660788826395580466708824,4953412325525289651086730443567098343730966,22873302288206466754758793232467436030071524731072

%N Number of tilings of an n X n square using dominoes and right trominoes.

%H Alois P. Heinz, <a href="/A219994/b219994.txt">Table of n, a(n) for n = 0..17</a>

%e a(3) = 8, because there are 8 tilings of a 3 X 3 square using dominoes and right trominoes:

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

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

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

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

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

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

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

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

%Y Main diagonal of A219987.

%Y Cf. A233807, A364504.

%K nonn

%O 0,3

%A _Alois P. Heinz_, Dec 02 2012