%I #15 May 09 2022 17:44:16

%S 1,1,5,39,2023,249651,128938297,207866584389,1208344842789831,

%T 23649239068131551559,1609120545126107661426575,

%U 375082120094104660413783094451,301522432794951154854984388046484015,833441700776362178606942848178200903068675,7931715551857283775957120938092133944383839378911

%N Number of tilings of an n X n square using right trominoes and 1 X 1 tiles.

%H Alois P. Heinz, <a href="/A220061/b220061.txt">Table of n, a(n) for n = 0..16</a>

%e a(2) = 5, because there are 5 tilings of a 2 X 2 square using right trominoes and 1 X 1 tiles:

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

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

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

%Y Main diagonal of A220054.

%Y Cf. A233807.

%K nonn

%O 0,3

%A _Alois P. Heinz_, Dec 03 2012