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A219975 Number of tilings of an n X n square using straight (3 X 1) trominoes and 2 X 2 tiles. 2
1, 0, 1, 2, 3, 28, 267, 2744, 66653, 2766100, 141365332, 13305552648, 2149055591278 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,4
LINKS
EXAMPLE
a(4) = 3, because there are 3 tilings of a 4 X 4 square using straight (3 X 1) trominoes and 2 X 2 tiles:
._._____. ._____._. ._._._._.
| |_____| |_____| | | . | . |
| | . | | | | . | | |___|___|
|_|___| | | |___|_| | . | . |
|_____|_| |_|_____| |___|___| .
CROSSREFS
Main diagonal of A219967.
Cf. A233807.
Sequence in context: A371115 A206592 A126266 * A319146 A206591 A003017
KEYWORD
nonn,more
AUTHOR
Alois P. Heinz, Dec 02 2012
EXTENSIONS
a(12) from Alois P. Heinz, Sep 24 2014
STATUS
approved

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Last modified April 18 04:56 EDT 2024. Contains 371767 sequences. (Running on oeis4.)