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A066655
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Number of partitions of n*(n-1)/2.
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7
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1, 1, 3, 11, 42, 176, 792, 3718, 17977, 89134, 451276, 2323520, 12132164, 64112359, 342325709, 1844349560, 10015581680, 54770336324, 301384802048, 1667727404093, 9275102575355, 51820051838712, 290726957916112, 1637293969337171, 9253082936723602
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OFFSET
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1,3
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COMMENTS
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Number of partitions of the number of edges of the complete graph of order n, K_n.
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LINKS
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FORMULA
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a(n) = p(n*(n-1)/2) = A000041(n*(n-1)/2).
a(n) ~ exp(Pi*sqrt(n*(n-1)/3))/(2*sqrt(3)*n*(n - 1)). - Ilya Gutkovskiy, Jan 13 2017
a(n) ~ exp(Pi*(n - 1/2) / sqrt(3)) / (2*sqrt(3)*n^2). - Vaclav Kotesovec, May 17 2018
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EXAMPLE
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a(4) = p(6) = 11.
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MATHEMATICA
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Table[PartitionsP[n(n-1)/2], {n, 1, 30}]
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PROG
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(MuPAD) combinat::partitions::count(binomial(n+2, n)) $n=-1..40 // Zerinvary Lajos, Apr 16 2007
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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