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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

Alois P. Heinz, Table of n, a(n) for n = 0..50

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 A043014

Adjacent sequences:  A219970 A219971 A219972 * A219974 A219975 A219976

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Dec 02 2012

STATUS

approved

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Last modified May 25 22:51 EDT 2022. Contains 354073 sequences. (Running on oeis4.)