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A219994
Number of tilings of an n X n square using dominoes and right trominoes.
7
1, 0, 2, 8, 380, 21272, 5350806, 3238675344, 6652506271144, 38896105985522272, 711716770252031164458, 38776997923112110535353528, 6460929292946758939597712150496, 3245656750963660788826395580466708824, 4953412325525289651086730443567098343730966, 22873302288206466754758793232467436030071524731072
OFFSET
0,3
LINKS
EXAMPLE
a(3) = 8, because there are 8 tilings of a 3 X 3 square using dominoes and right trominoes:
.___._. .___._. .___._. .___._.
|___| | |___| | |___| | |_. | |
| ._|_| | | |_| | |___| | |_|_|
|_|___| |_|___| |_|___| |_|___|
._.___. ._.___. ._.___. ._.___.
| |___| | | ._| | |___| | |___|
|___| | |_|_| | |_|_. | |_| | |
|___|_| |___|_| |___|_| |___|_| .
CROSSREFS
Main diagonal of A219987.
Sequence in context: A009836 A012342 A012348 * A014185 A367998 A009808
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Dec 02 2012
STATUS
approved