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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: A371115 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 April 18 04:56 EDT 2024. Contains 371767 sequences. (Running on oeis4.)