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A219972
Number of tilings of an 8 X n rectangle using straight (3 X 1) trominoes and 2 X 2 tiles.
2
1, 0, 4, 19, 70, 456, 2530, 12343, 66653, 372429, 1910822, 10162059, 55583124, 291195073, 1550518247, 8363883923, 44269140576, 235940940726, 1264437357202, 6723179849519, 35846240541026, 191571690239220, 1020536749613565, 5442225134864810, 29051213879574079
OFFSET
0,3
LINKS
EXAMPLE
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:
.___. .___. .___. .___.
| | | | | | | | | |
|___| |___| | | | | | |
| | | | | |_|_| |_|_|
|___| | | | | | | | |
| | |_|_| |___| | | |
|___| | | | | | | |_|_|
| | | | | | | | | |
|___| |_|_| |_|_| |___|
CROSSREFS
Column k=8 of A219967.
Sequence in context: A129019 A167247 A267192 * A284224 A268214 A027208
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Dec 02 2012
STATUS
approved