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A327365
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Triangle read by rows where T(n,k) is the number of unlabeled simple graphs covering n vertices with vertex-connectivity >= k.
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2
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1, 0, 0, 1, 1, 0, 2, 2, 1, 0, 7, 6, 3, 1, 0, 23, 21, 10, 3, 1, 0, 122, 112, 56, 17, 4, 1, 0, 888, 853, 468, 136, 25, 4, 1, 0, 11302, 11117, 7123, 2388, 384, 39, 5, 1, 0, 262322, 261080, 194066, 80890, 14480, 1051, 59, 5, 1, 0, 11730500, 11716571, 9743542, 5114079, 1211735, 102630, 3211, 87, 6, 1, 0
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OFFSET
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0,7
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COMMENTS
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A graph is covering if there are no isolated vertices.
The vertex-connectivity of a graph is the minimum number of vertices that must be removed (along with any incident edges) to obtain a non-connected graph or singleton.
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LINKS
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EXAMPLE
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Triangle begins:
1
0 0
1 1 0
2 2 1 0
7 6 3 1 0
23 21 10 3 1 0
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CROSSREFS
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Column k = 2 is A002218 (2-connected graphs), if we assume A002218(2) = 0.
The non-covering version is A327805, from which this sequence differs only in the k = 0 column.
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KEYWORD
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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