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A230031 Number A(n,k) of tilings of a k X n rectangle using tetrominoes of any shape; square array A(n,k), n>=0, k>=0, read by antidiagonals. 18
1, 1, 1, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 1, 1, 1, 0, 0, 1, 1, 1, 0, 4, 0, 4, 0, 1, 1, 0, 0, 23, 23, 0, 0, 1, 1, 0, 9, 0, 117, 0, 9, 0, 1, 1, 1, 0, 0, 454, 454, 0, 0, 1, 1, 1, 0, 25, 0, 2003, 0, 2003, 0, 25, 0, 1, 1, 0, 0, 997, 9157, 0, 0, 9157, 997, 0, 0, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,24

LINKS

Alois P. Heinz, Antidiagonals n = 0..20, flattened

S. Butler, J. Ekstrand, S. Osborne, TETRIS Tiling, AMS Spring Central Sectional, Iowa State University, April 27-28 2013

R. S. Harris, Counting Polyomino Tilings

Wikipedia, Tetris

Wikipedia, Tetromino

FORMULA

A(n,k) = 0 <=> n*k mod 4 > 0.

EXAMPLE

A(4,2) = A(2,4) = 4:

  ._______.  ._______.  ._______.  ._______.

  |   |   |  |_______|  | |___. |  | .___| |

  |___|___|  |_______|  |_____|_|  |_|_____|.

Square array A(n,k) begins:

  1, 1,  1,   1,     1,      1,        1,         1,           1, ...

  1, 0,  0,   0,     1,      0,        0,         0,           1, ...

  1, 0,  1,   0,     4,      0,        9,         0,          25, ...

  1, 0,  0,   0,    23,      0,        0,         0,         997, ...

  1, 1,  4,  23,   117,    454,     2003,      9157,       40899, ...

  1, 0,  0,   0,   454,      0,        0,         0,      800290, ...

  1, 0,  9,   0,  2003,      0,   178939,         0,    22483347, ...

  1, 0,  0,   0,  9157,      0,        0,         0,   657253434, ...

  1, 1, 25, 997, 40899, 800290, 22483347, 657253434, 19077209438, ...

CROSSREFS

Columns (or rows) include: A000012, A007598, A232757, A174248, A232758, A232684, A232759, A232698, A247113, A232722.

Bisection of main diagonal (even part) gives A263425.

Cf. A099390, A233320, A233427.

Sequence in context: A028618 A147986 A147988 * A019920 A246130 A010675

Adjacent sequences:  A230028 A230029 A230030 * A230032 A230033 A230034

KEYWORD

nonn,tabl

AUTHOR

Alois P. Heinz, Nov 29 2013

STATUS

approved

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Last modified February 20 12:57 EST 2019. Contains 320327 sequences. (Running on oeis4.)