login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A219971 Number of tilings of a 7 X n rectangle using straight (3 X 1) trominoes and 2 X 2 tiles. 2
1, 0, 3, 13, 31, 170, 804, 2744, 12343, 55657, 214485, 923990, 4008013, 16241904, 68963484, 293830787, 1216393406, 5135225641, 21711233759, 90692128053, 381960417890, 1609647053073, 6749229887672, 28396742081001, 119506154362773, 501879008939056 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

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

EXAMPLE

a(2) = 3, because there are 3 tilings of a 7 X 2 rectangle using straight (3 X 1) trominoes and 2 X 2 tiles:

._._.   .___.   .___.

| | |   |   |   |   |

| | |   |___|   |___|

|_|_|   | | |   |   |

|   |   | | |   |___|

|___|   |_|_|   | | |

|   |   |   |   | | |

|___|   |___|   |_|_|

CROSSREFS

Column k=7 of A219967.

Sequence in context: A339945 A154834 A159047 * A073337 A128067 A052493

Adjacent sequences:  A219968 A219969 A219970 * A219972 A219973 A219974

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Dec 02 2012

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified July 1 02:58 EDT 2022. Contains 354947 sequences. (Running on oeis4.)