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A226371
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Number of tilings of a 7 X n rectangle using integer-sided square tiles of area > 1.
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2
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1, 0, 0, 0, 0, 0, 7, 1, 0, 0, 2, 0, 57, 16, 1, 0, 32, 4, 463, 197, 29, 1, 392, 100, 3767, 2150, 518, 46, 4267, 1668, 30763, 21953, 7454, 1128, 43531, 23057, 252755, 215070, 94769, 20728, 426847, 285548, 2094102, 2050219, 1112227, 321677, 4080855, 3290655
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OFFSET
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0,7
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LINKS
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FORMULA
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G.f.: (-x^12-x^9+2*x^6+x^3-1) / (x^19 -x^18 -x^16 -x^15 -2*x^13 -7*x^12 +x^10 -8*x^9 +x^7 +9*x^6 +x^3-1).
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EXAMPLE
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a(10) = 2:
._._._._._._._._._._. ._._._._._._._._._._.
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|___|___|___|___|___| |_________|_________|
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MAPLE
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a:= n-> coeff(series((-x^12-x^9+2*x^6+x^3-1) / (x^19 -x^18 -x^16 -x^15 -2*x^13 -7*x^12 +x^10 -8*x^9 +x^7 +9*x^6 +x^3-1), x, n+1), x, n):
seq(a(n), n=0..70);
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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