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A220061 Number of tilings of an n X n square using right trominoes and 1 X 1 tiles. 5
1, 1, 5, 39, 2023, 249651, 128938297, 207866584389, 1208344842789831, 23649239068131551559, 1609120545126107661426575, 375082120094104660413783094451, 301522432794951154854984388046484015, 833441700776362178606942848178200903068675, 7931715551857283775957120938092133944383839378911 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..16

EXAMPLE

a(2) = 5, because there are 5 tilings of a 2 X 2 square using right trominoes and 1 X 1 tiles:

._._. ._._. .___. .___. ._._.

|_|_| | |_| | ._| |_. | |_| |

|_|_| |___| |_|_| |_|_| |___|

CROSSREFS

Main diagonal of A220054.

Cf. A233807.

Sequence in context: A118991 A253920 A156378 * A299815 A222366 A029538

Adjacent sequences: A220058 A220059 A220060 * A220062 A220063 A220064

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Dec 03 2012

STATUS

approved

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Last modified February 5 18:47 EST 2023. Contains 360087 sequences. (Running on oeis4.)