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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

Table of n, a(n) for n=0..12.

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: A074233 A206592 A126266 * A319146 A206591 A003017

Adjacent sequences:  A219972 A219973 A219974 * A219976 A219977 A219978

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 July 2 09:31 EDT 2022. Contains 354998 sequences. (Running on oeis4.)