A219970 Number of tilings of a 6 X n rectangle using straight (3 X 1) trominoes and 2 X 2 tiles.

1, 1, 2, 8, 21, 65, 267, 804, 2530, 9407, 29876, 96530, 337607, 1100968, 3612017, 12284181, 40538721, 133971666, 450045654, 1492504271, 4949649998, 16537407509, 54951656907, 182545459254, 608458757050, 2023395434235, 6727009100372, 22399013790607

Offset: 0

Author

Alois P. Heinz, Dec 02 2012

Keywords

• nonn

Examples

			a(2) = 2, because there are 2 tilings of a 6 X 2 rectangle using straight (3 X 1) trominoes and 2 X 2 tiles:
._._.   .___.
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| | |   |   |
|_|_|   |___|
		

Links

• Alois P. Heinz, Table of n, a(n) for n = 0..600

Crossrefs

Column k=6 of A219967.