A232684 Number of tilings of a 6 X 2n rectangle with 3n tetrominoes of any shape.

1, 9, 2003, 178939, 22483347, 2569437089, 304446920314, 35704534261665, 4203065267122878, 494232382069456694, 58138539945306221167, 6838279451118114249916, 804352962762109905924360, 94610929453211737452277488, 11128526714790919845521179844

Offset: 0

Author

Alois P. Heinz, Nov 27 2013

Keywords

• nonn

Examples

			a(1) = 9:
.___. .___. .___. .___. .___. .___. .___. .___. .___.
|   | | | | |   | |_. | |   | | ._| |   | | ._| |_. |
|___| | | | |___| | | | |___| | | | |___| | | | | | |
|   | | | | | | | | |_| |_. | |_| | | ._| |_| | | |_|
|___| |_|_| | | | |___| | | | |___| | | | | | | | | |
|   | |   | | | | |   | | |_| |   | |_| | | |_| |_| |
|___| |___| |_|_| |___| |___| |___| |___| |___| |___|.
		

Links

• Alois P. Heinz, Table of n, a(n) for n = 0..300
• S. Butler, J. Ekstrand, S. Osborne, TETRIS Tiling, AMS Spring Central Sectional, Iowa State University, April 27-28 2013
• Wikipedia, Tetromino

Crossrefs

Cf. A174248, A232698, A232722.

Even bisection of column k=6 of A230031.