A220768 Number of tilings of a 2 X n rectangle using integer-sided rectangular tiles of equal area.

1, 2, 4, 6, 9, 11, 21, 24, 43, 62, 102, 147, 259, 380, 636, 1003, 1640, 2587, 4258, 6768, 11053, 17740, 28806, 46371, 75318, 121405, 196800, 317874, 514870, 832043, 1347376, 2178312, 3526218, 5703039, 9230054, 14930386, 24162313, 39088172, 63252756, 102334540

Offset

0,2

Comments

a(n+1)/a(n) tends to phi = (1+sqrt(5))/2 = A001622. - Vaclav Kotesovec, Dec 21 2012

Links

Alois P. Heinz, Table of n, a(n) for n = 0..1000

Example

a(5) = 11:
._________. ._________. ._________. ._________. ._________.
|         | |_________| | | | | | | |___| | | | | |___| | |
|_________| |_________| |_|_|_|_|_| |___|_|_|_| |_|___|_|_|
._________. ._________. ._________. ._________. ._________.
| | |___| | | | | |___| |___|___| | |___| |___| | |___|___|
|_|_|___|_| |_|_|_|___| |___|___|_| |___|_|___| |_|___|___|
._________.
|_|_|_|_|_|
|_|_|_|_|_|

Crossrefs

Column k=2 of A220777.

Sequence in context: A153196 A247185 A237685 * A077220 A128716 A258934

Adjacent sequences: A220765 A220766 A220767 * A220769 A220770 A220771

Keyword

nonn

Author

Alois P. Heinz, Dec 19 2012

Status

approved