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A354131

Number of tilings of a 2 X n rectangle using 2 X 2 and 1 X 1 tiles, right trominoes and dominoes.

1, 2, 12, 48, 216, 936, 4104, 17928, 78408, 342792, 1498824, 6553224, 28652616, 125277192, 547747272, 2394904968, 10471198536, 45783025416, 200176267464, 875226954888, 3826738469448, 16731577137672, 73155162229704, 319854949515144, 1398495821923656

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OFFSET

0,2

COMMENTS

Tiling algorithm see A351322.

LINKS

Table of n, a(n) for n=0..24.

Index entries for linear recurrences with constant coefficients, signature (3,6).

FORMULA

G.f.: (1 - x) / (1 - 3*x - 6*x^2).

a(n) = 3*a(n-1) + 6*a(n-2).

EXAMPLE

a(3)=48

Number of tilings without a 2 X 2 square: 44, see A353878.

Number of other tilings: 4

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PROG

(Maxima), see A352589.

CROSSREFS

Cf. A351322, A352589, A353878, A354130, A354132.

Sequence in context: A001815 A347324 A333728 * A370696 A052569 A221663

Adjacent sequences: A354128 A354129 A354130 * A354132 A354133 A354134

KEYWORD

nonn,easy

AUTHOR

Gerhard Kirchner, May 18 2022

STATUS

approved

URL: https://oeis.org/A354131

⇱ A354131 - OEIS