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A234931
Number of tilings of a 5 X n rectangle using n pentominoes of shapes F, U, N.
11
1, 0, 0, 0, 2, 0, 0, 0, 4, 0, 8, 0, 16, 0, 40, 0, 64, 16, 200, 96, 504, 464, 1528, 1664, 4376, 5616, 12792, 18192, 38264, 58384, 115832, 186368, 355808, 589344, 1095408, 1853664, 3383656, 5802016, 10470376, 18125280, 32461312, 56552736, 100782696, 176318464
OFFSET
0,5
LINKS
Wikipedia, Pentomino
FORMULA
G.f.: (4*x^20 +4*x^18 +8*x^16 -3*x^14 +4*x^13 -5*x^12 -2*x^11 +3*x^10 -2*x^9 +6*x^8 -2*x^7 +2*x^6 -2*x^5 -x^4 +2*x -1) / (-8*x^22 -28*x^20 -6*x^18 +8*x^17 +26*x^16 +4*x^15 +7*x^14 -8*x^13 -9*x^12 -14*x^11 +7*x^10 +2*x^9 +8*x^8 -2*x^7 +2*x^6 -6*x^5 +x^4 +2*x -1).
EXAMPLE
a(4) = 2:
._______. ._______.
| | ._. | | ._. | |
| |_| |_| |_| |_| |
|_. |_. | | ._| ._|
| |_| | | | | |_| |
|_____|_| |_|_____|.
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Jan 01 2014
STATUS
approved