A219871 Number of tilings of an 8 X n rectangle using dominoes and straight (3 X 1) trominoes.

1, 4, 123, 5233, 161800, 6155230, 223026907, 8061851335, 295743829064, 10750194262698, 392127322268846, 14301080443962397, 521186161714401053, 19005127884701974465, 692863015545590519355, 25260000472133325186613, 920954865421382858310101

Offset

0,2

Links

Alois P. Heinz, Table of n, a(n) for n = 0..200

Example

a(1) = 4, because there are 4 tilings of an 8 X 1 rectangle using dominoes and straight (3 X 1) trominoes:
._.    ._.    ._.    ._.
| |    | |    | |    | |
| |    | |    |_|    |_|
|_|    |_|    | |    | |
| |    | |    | |    |_|
| |    |_|    |_|    | |
|_|    | |    | |    |_|
| |    | |    | |    | |
|_|    |_|    |_|    |_|

Crossrefs

Column k=8 of A219866.

Sequence in context: A268006 A144993 A064681 * A263550 A232592 A005936

Adjacent sequences: A219868 A219869 A219870 * A219872 A219873 A219874

Keyword

nonn

Author

Alois P. Heinz, Nov 30 2012

Status

approved