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Search: a269958 -id:a269958
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Number A(n,k) of tilings of a k X n rectangle using trominoes of any shape; square array A(n,k), n>=0, k>=0, read by antidiagonals.
+10
17
1, 1, 1, 1, 0, 1, 1, 0, 0, 1, 1, 1, 0, 1, 1, 1, 0, 3, 3, 0, 1, 1, 0, 0, 10, 0, 0, 1, 1, 1, 0, 23, 23, 0, 1, 1, 1, 0, 11, 62, 0, 62, 11, 0, 1, 1, 0, 0, 170, 0, 0, 170, 0, 0, 1, 1, 1, 0, 441, 939, 0, 939, 441, 0, 1, 1, 1, 0, 41, 1173, 0, 8342, 8342, 0, 1173, 41, 0, 1
OFFSET
0,18
COMMENTS
Every row and column satisfies a linear recurrence. - Peter Kagey, Jul 17 2019
LINKS
Wikipedia, Tromino
FORMULA
A(n,k) = 0 <=> n*k mod 3 > 0.
EXAMPLE
Square array A(n,k) begins:
1, 1, 1, 1, 1, 1, 1, ...
1, 0, 0, 1, 0, 0, 1, ...
1, 0, 0, 3, 0, 0, 11, ...
1, 1, 3, 10, 23, 62, 170, ...
1, 0, 0, 23, 0, 0, 939, ...
1, 0, 0, 62, 0, 0, 8342, ...
1, 1, 11, 170, 939, 8342, 80092, ...
1, 0, 0, 441, 0, 0, 614581, ...
1, 0, 0, 1173, 0, 0, 5271923, ...
KEYWORD
nonn,tabl
AUTHOR
Alois P. Heinz, Dec 07 2013
STATUS
approved

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