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A219970 Number of tilings of a 6 X n rectangle using straight (3 X 1) trominoes and 2 X 2 tiles. 2
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 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
LINKS
EXAMPLE
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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CROSSREFS
Column k=6 of A219967.
Sequence in context: A123285 A143212 A316270 * A107361 A185309 A318040
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Dec 02 2012
STATUS
approved

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Last modified April 20 02:14 EDT 2024. Contains 371798 sequences. (Running on oeis4.)