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A046984 Number of ways to tile a 4 X 3n rectangle with right trominoes. 1
1, 4, 18, 88, 468, 2672, 16072, 100064, 636368, 4097984, 26579488, 173093760, 1129796928, 7383588608, 48287978624, 315921649152, 2067346607360, 13530037877760, 88555066819072, 579620448450560, 3793872862974976 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

REFERENCES

Suggested on p. 96 of 1994 edition of "Polyominoes" by Samuel W. Golomb.

LINKS

Table of n, a(n) for n=0..20.

Preprint and figures

C. Moore, [math/9905012] Some Polyomino Tilings of the Plane

Index entries for linear recurrences with constant coefficients, signature (10, -22, -4).

FORMULA

G.f.: (1 - 6*x)/(1 - 10*x + 22*x^2 + 4*x^3).

a(0)=1, a(1)=4, a(2)=18, a(n)=10*a(n-1)-22*a(n-2)-4*a(n-3). - Harvey P. Dale, Mar 31 2012

MATHEMATICA

CoefficientList[Series[(1-6x)/(1-10x+22x^2+4x^3), {x, 0, 40}], x] (* or *) LinearRecurrence[{10, -22, -4}, {1, 4, 18}, 40] (* Harvey P. Dale, Mar 31 2012 *)

PROG

(PARI) a(n)=([0, 1, 0; 0, 0, 1; -4, -22, 10]^n*[1; 4; 18])[1, 1] \\ Charles R Greathouse IV, Feb 10 2017

CROSSREFS

Sequence in context: A006629 A068764 A127394 * A129323 A000305 A200029

Adjacent sequences:  A046981 A046982 A046983 * A046985 A046986 A046987

KEYWORD

nonn,easy,nice

AUTHOR

Cristopher Moore (moore(AT)santafe.edu)

EXTENSIONS

More terms from James A. Sellers

STATUS

approved

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Last modified February 23 03:41 EST 2018. Contains 299473 sequences. (Running on oeis4.)