A219868 Number of tilings of a 5 X n rectangle using dominoes and straight (3 X 1) trominoes.

1, 2, 15, 143, 1069, 9612, 82634, 707903, 6155230, 53074167, 458901955, 3968548571, 34293794622, 296497719200, 2563023778341, 22155553744380, 191528023181443, 1655649630655481, 14312296720331975, 123722938782920490, 1069522524403416934, 9245501816227527991

Offset

0,2

Links

Alois P. Heinz, Table of n, a(n) for n = 0..500

Example

a(2) = 15, because there are 15 tilings of a 5 X 2 rectangle using dominoes and straight (3 X 1) trominoes:
.___.  .___.  .___.  .___.  .___.  .___.  .___.  .___.
| | |  |___|  | | |  |___|  | | |  |___|  | | |  |___|
| | |  |___|  |_|_|  | | |  | | |  |___|  |_|_|  | | |
|_|_|  |___|  |___|  |_|_|  |_|_|  |___|  |___|  |_|_|
| | |  | | |  | | |  | | |  |___|  |___|  |___|  |___|
|_|_|  |_|_|  |_|_|  |_|_|  |___|  |___|  |___|  |___|
.___.  .___.  .___.  .___.  ._._.  ._._.  .___.
| | |  | | |  |___|  |___|  | | |  | | |  |___|
|_|_|  |_|_|  |___|  |___|  |_| |  | |_|  | | |
| | |  | | |  | | |  | | |  | |_|  |_| |  | | |
| | |  |_|_|  | | |  |_|_|  | | |  | | |  |_|_|
|_|_|  |___|  |_|_|  |___|  |_|_|  |_|_|  |___|

Crossrefs

Column k=5 of A219866.

Sequence in context: A288950 A005415 A371523 * A224885 A371575 A253571

Adjacent sequences: A219865 A219866 A219867 * A219869 A219870 A219871

Keyword

nonn

Author

Alois P. Heinz, Nov 30 2012

Status

approved