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A219973 Number of tilings of a 9 X n rectangle using straight (3 X 1) trominoes and 2 X 2 tiles. 2
1, 1, 5, 35, 165, 1177, 9407, 55657, 372429, 2766100, 17671945, 118674685, 837152398, 5531816082, 37328192350, 257252634864, 1725117502706, 11666552132346, 79612474584518, 537157628862720, 3636277021289585, 24711657036469040, 167150255133278869 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
LINKS
EXAMPLE
a(2) = 5, because there are 5 tilings of a 9 X 2 rectangle using straight (3 X 1) trominoes and 2 X 2 tiles:
.___. .___. .___. .___. .___.
| | | | | | | | | | | |
| | | | | | |___| |___| |___|
|_|_| |_|_| | | | | | | |
| | | | | | | | |___| |___|
| | | |___| |_|_| | | | | |
|_|_| | | | | | | | |___|
| | | |___| |___| |_|_| | | |
| | | | | | | | | | | |
|_|_| |___| |___| |___| |_|_|
CROSSREFS
Column k=9 of A219967.
Sequence in context: A184707 A124793 A048515 * A100739 A329762 A359520
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Dec 02 2012
STATUS
approved

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Last modified April 21 03:36 EDT 2024. Contains 371850 sequences. (Running on oeis4.)