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A220130
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Number of tilings of an n X 5 rectangle using integer-sided rectangular tiles of area n.
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2
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1, 1, 8, 4, 16, 2, 13, 1, 16, 4, 9, 1, 21, 1, 8, 5, 16, 1, 13, 1, 17, 4, 8, 1, 21, 2, 8, 4, 16, 1, 14, 1, 16, 4, 8, 2, 21, 1, 8, 4, 17, 1, 13, 1, 16, 5, 8, 1, 21, 1, 9, 4, 16, 1, 13, 2, 16, 4, 8, 1, 22, 1, 8, 4, 16, 2, 13, 1, 16, 4, 9, 1, 21, 1, 8, 5, 16, 1
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OFFSET
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0,3
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COMMENTS
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1 followed by period 60: (1, 8, ..., 22) repeated; offset 0.
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LINKS
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FORMULA
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G.f.: see Maple program.
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EXAMPLE
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a(3) = 4, because there are 4 tilings of a 3 X 5 rectangle using integer-sided rectangular tiles of area 3:
._._._._._. ._____._._. ._._____._. ._._._____.
| | | | | | |_____| | | | |_____| | | | |_____|
| | | | | | |_____| | | | |_____| | | | |_____|
|_|_|_|_|_| |_____|_|_| |_|_____|_| |_|_|_____|
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MAPLE
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gf:= -(21*x^12 +22*x^11 +51*x^10 +56*x^9 +80*x^8 +65*x^7 +72*x^6 +45*x^5 +40*x^4 +16*x^3 +11*x^2 +2*x +1) / (x^12 +x^11 +2*x^10 +2*x^9 +2*x^8 +x^7 -x^5 -2*x^4 -2*x^3 -2*x^2 -x -1):
a:= n-> coeff(series(gf, x, n+1), x, n):
seq(a(n), n=0..100);
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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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