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A183566
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Number of partitions of n containing a clique of size 9.
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12
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1, 0, 1, 1, 2, 2, 4, 4, 7, 9, 13, 15, 23, 27, 38, 47, 63, 77, 103, 126, 165, 201, 258, 315, 401, 487, 611, 743, 924, 1118, 1382, 1664, 2041, 2455, 2989, 3583, 4340, 5185, 6248, 7446, 8930, 10604, 12668, 15002, 17848, 21083, 24987, 29435, 34776, 40860
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OFFSET
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9,5
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COMMENTS
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All parts of a number partition with the same value form a clique. The size of a clique is the number of elements in the clique.
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LINKS
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FORMULA
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G.f.: (1-Product_{j>0} (1-x^(9*j)+x^(10*j))) / (Product_{j>0} (1-x^j)).
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EXAMPLE
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a(12) = 1, because 1 partition of 12 contains (at least) one clique of size 9: [1,1,1,1,1,1,1,1,1,3].
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MAPLE
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b:= proc(n, i) option remember; `if`(n=0, [1, 0], `if`(i<1, [0, 0],
add((l->`if`(j=9, [l[1]$2], l))(b(n-i*j, i-1)), j=0..n/i)))
end:
a:= n-> (l-> l[2])(b(n, n)):
seq(a(n), n=9..60);
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MATHEMATICA
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max=60; f=(1-Product[1-x^(9j)+x^(10j), {j, 1, max}])/Product[1-x^j, {j, 1, max}]; s=Series[f, {x, 0, max}]; Drop[CoefficientList[s, x], 9] (* Jean-François Alcover, Oct 01 2014 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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