A220061 Number of tilings of an n X n square using right trominoes and 1 X 1 tiles.

1, 1, 5, 39, 2023, 249651, 128938297, 207866584389, 1208344842789831, 23649239068131551559, 1609120545126107661426575, 375082120094104660413783094451, 301522432794951154854984388046484015, 833441700776362178606942848178200903068675, 7931715551857283775957120938092133944383839378911

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 A371557 A222366

Adjacent sequences: A220058 A220059 A220060 * A220062 A220063 A220064

Keyword

nonn

Author

Alois P. Heinz, Dec 03 2012

Status

approved