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
Offset: 0
Examples
a(3)=48 Number of tilings without a 2 X 2 square: 44, see A353878. Number of other tilings: 4 ___ _ ___ _ _ ___ _ ___ | | | | |_| | | | |_| | |___|_| |___|_| |_|___| |_|___|
Links
- Index entries for linear recurrences with constant coefficients, signature (3,6).
Programs
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Maxima
, see A352589.
Formula
G.f.: (1 - x) / (1 - 3*x - 6*x^2).
a(n) = 3*a(n-1) + 6*a(n-2).
Comments