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A354132
Number of tilings of a 3 X n rectangle using 2 X 2 and 1 X 1 tiles, right trominoes and dominoes.
2
1, 3, 48, 405, 4185, 40320, 397755, 3892293, 38193444, 374425263, 3671810235, 36003770640, 353046480345, 3461866214283, 33946152068808, 332866572321933, 3263999126947497, 32005882711563552, 313840950402409011, 3077438640586986141, 30176522977460549436
OFFSET
0,2
COMMENTS
Tiling algorithm see A351322.
FORMULA
G.f.: (1 - 3*x - 8*x^2 + 3*x^3 - x^4) / (1 - 6*x - 38*x^2 + 68*x^4 - 24*x^5 + 3*x^6).
a(n) = 6*a(n-1) + 38*a(n-2) - 68*a(n-4) + 24*a(n-5) - 3*a(n-6).
EXAMPLE
a(2) = 48, see 2 X 3, A354131.
PROG
(Maxima), see A352589.
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Gerhard Kirchner, May 18 2022
STATUS
approved