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A248102 Number of tilings of a 5 X 2n rectangle using 2n pentominoes of shapes N, Y. 2
1, 0, 0, 18, 24, 238, 842, 4360, 25900, 112178, 613140, 2941170, 14789274, 74895336, 369603312, 1866863986, 9294391952, 46543456838, 233028690018, 1164275409976, 5830080180396, 29149585256266, 145845002931724, 729627382873090, 3649578988919810 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

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

Wikipedia, Pentomino

FORMULA

G.f.: (8*x^15 -52*x^14 -64*x^13 +1087*x^12 -2822*x^11 +2369*x^10 +810*x^9 -2047*x^8 +300*x^7 +122*x^6 +208*x^5 +x^4 +6*x^3 +9*x^2 +2*x -1) / (24*x^15 +4*x^14 -680*x^13 +2673*x^12 -4212*x^11 +2139*x^10 +1574*x^9 -2141*x^8 +456*x^7 -160*x^6 +236*x^5 -11*x^4 +24*x^3 +9*x^2 +2*x -1).

EXAMPLE

a(3) = 18:

._______._._.        .___._______.        .___._______.

|_. .___| | |        |_. |___. ._|        |_. |___. ._|

| |_| | ._| |        | |_____|_| |        | |_____|_| |

| ._| | |_. |        | |___. ._| |        | |___. |_. |

| | ._|_| |_|        | ._| |_|_. |        | ._| |___| |

|_|_|_______| (*2)   |_|_______|_| (*8)   |_|_______|_| (*8)  .

CROSSREFS

Cf. A174249, A233427, A234312, A234931, A247680, A247443.

Sequence in context: A092536 A214620 A125261 * A166646 A109144 A166471

Adjacent sequences:  A248099 A248100 A248101 * A248103 A248104 A248105

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Oct 01 2014

STATUS

approved

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Last modified November 19 22:34 EST 2019. Contains 329323 sequences. (Running on oeis4.)