A219972 Number of tilings of an 8 X n rectangle using straight (3 X 1) trominoes and 2 X 2 tiles.

1, 0, 4, 19, 70, 456, 2530, 12343, 66653, 372429, 1910822, 10162059, 55583124, 291195073, 1550518247, 8363883923, 44269140576, 235940940726, 1264437357202, 6723179849519, 35846240541026, 191571690239220, 1020536749613565, 5442225134864810, 29051213879574079

Offset

0,3

Links

Alois P. Heinz, Table of n, a(n) for n = 0..100

Example

a(2) = 4, because there are 4 tilings of an 8 X 2 rectangle using straight (3 X 1) trominoes and 2 X 2 tiles:
.___.   .___.   .___.   .___.
|   |   |   |   | | |   | | |
|___|   |___|   | | |   | | |
|   |   | | |   |_|_|   |_|_|
|___|   | | |   |   |   | | |
|   |   |_|_|   |___|   | | |
|___|   | | |   | | |   |_|_|
|   |   | | |   | | |   |   |
|___|   |_|_|   |_|_|   |___|

Crossrefs

Column k=8 of A219967.

Sequence in context: A129019 A167247 A267192 * A284224 A268214 A027208

Adjacent sequences: A219969 A219970 A219971 * A219973 A219974 A219975

Keyword

nonn

Author

Alois P. Heinz, Dec 02 2012

Status

approved