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A219868 Number of tilings of a 5 X n rectangle using dominoes and straight (3 X 1) trominoes. 3
1, 2, 15, 143, 1069, 9612, 82634, 707903, 6155230, 53074167, 458901955, 3968548571, 34293794622, 296497719200, 2563023778341, 22155553744380, 191528023181443, 1655649630655481, 14312296720331975, 123722938782920490, 1069522524403416934, 9245501816227527991 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
LINKS
EXAMPLE
a(2) = 15, because there are 15 tilings of a 5 X 2 rectangle using dominoes and straight (3 X 1) trominoes:
.___. .___. .___. .___. .___. .___. .___. .___.
| | | |___| | | | |___| | | | |___| | | | |___|
| | | |___| |_|_| | | | | | | |___| |_|_| | | |
|_|_| |___| |___| |_|_| |_|_| |___| |___| |_|_|
| | | | | | | | | | | | |___| |___| |___| |___|
|_|_| |_|_| |_|_| |_|_| |___| |___| |___| |___|
.___. .___. .___. .___. ._._. ._._. .___.
| | | | | | |___| |___| | | | | | | |___|
|_|_| |_|_| |___| |___| |_| | | |_| | | |
| | | | | | | | | | | | | |_| |_| | | | |
| | | |_|_| | | | |_|_| | | | | | | |_|_|
|_|_| |___| |_|_| |___| |_|_| |_|_| |___|
CROSSREFS
Column k=5 of A219866.
Sequence in context: A285449 A288950 A005415 * A224885 A253571 A111686
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Nov 30 2012
STATUS
approved

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Last modified March 4 09:05 EST 2024. Contains 370528 sequences. (Running on oeis4.)