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Search: id:A054548
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| A054548 |
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Triangular array giving number of labeled graphs on n unisolated nodes and k=0...n*(n-1)/2 edges. |
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+0
3
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| 0, 0, 1, 0, 0, 3, 1, 0, 0, 3, 16, 15, 6, 1, 0, 0, 0, 30, 135, 222, 205, 120, 45, 10, 1, 0, 0, 0, 15, 330, 1581, 3760, 5715, 6165, 4945, 2997, 1365, 455, 105, 15, 1, 0, 0, 0, 0, 315, 4410, 23604, 73755, 159390, 259105, 331716, 343161, 290745, 202755, 116175
(list; graph; listen)
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OFFSET
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1,6
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FORMULA
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a(n, k)=sum_{i=0..n} (-1)^(n-i)*C(n, i)*C(C(i, 2), k), k=0...n*(n-1)/2.
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EXAMPLE
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[0],[0,1],[0,0,3,1],[0,0,3,16,15,6,1],[0,0,0,30,135,222,205,120,45,10,1],...
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CROSSREFS
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Row sums give A006129. Cf. A054547.
Sequence in context: A085604 A144357 A122848 this_sequence A059202 A144452 A058865
Adjacent sequences: A054545 A054546 A054547 this_sequence A054549 A054550 A054551
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KEYWORD
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easy,nonn
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AUTHOR
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Vladeta Jovovic (vladeta(AT)eunet.rs), Apr 09 2000
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