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A372221
Number of tilings of a 5 X n rectangle using n pentominoes of shapes T, W, I, X.
2
1, 1, 1, 1, 1, 2, 3, 6, 9, 12, 16, 21, 41, 66, 106, 156, 219, 364, 558, 930, 1444, 2191, 3515, 5361, 8737, 13661, 21478, 34397, 53528, 86137, 135294, 215432, 345081, 546705, 879212, 1395476, 2239086, 3596427, 5767656, 9312008, 14949738, 24163742, 39045229
OFFSET
0,6
EXAMPLE
a(7) = 6:
._____________. ._____________. ._____________.
| |_________| | | | | | | | | | |_________| | |
| .___| |___. | | | | | | | | | |_________| | |
|_| ._| |_. |_| | | | | | | | | |_________| | |
| ._|_____|_. | | | | | | | | | |_________| | |
|_|_________|_| |_|_|_|_|_|_|_| |_________|_|_|
._____________. ._____________. ._____________.
| |_________| | | |_________| | | | |_________|
|_. |_. ._| ._| | |_________| | | | |_________|
| |___| |___| | | |_________| | | | |_________|
| .___|_|___. | | |_________| | | | |_________|
|_|_________|_| |_|_________|_| |_|_|_________| .
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Alois P. Heinz, Apr 22 2024
STATUS
approved