A128102 Number of 2 X 2 tiles in all tilings of a 4 X n rectangle with 1 X 1 and 2 X 2 square tiles.
0, 0, 5, 14, 69, 224, 805, 2610, 8545, 27068, 85209, 264406, 814509, 2488536, 7558093, 22827130, 68625657, 205455348, 612884929, 1822355742, 5402974789, 15977195792, 47135117493, 138757706946, 407679684497, 1195641350700
Offset: 0
Keywords
References
- S. Heubach, Tiling an m X n area with squares of size up to k X k (m <=5), Congressus Numerantium 140 (1999), pp. 43-64.
Links
- Index entries for linear recurrences with constant coefficients, signature (4,2,-16,-1,12,-4).
Crossrefs
Cf. A128101.
Programs
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Maple
g:=z^2*(5-6*z+3*z^2)/(1-2*z-3*z^2+2*z^3)^2: gser:=series(g,z=0,32): seq(coeff(gser,z,n),n=0..29);
Formula
G.f.=z^2*(5-6z+3z^2)/(1-2z-3z^2+2z^3)^2.
Comments