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Search: id:A123547
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| A123547 |
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Triangle read by rows: T(n,k) = number of unlabeled bicolored graphs with no isolated nodes having 2n nodes and k edges, with n nodes of each color. Here n >= 0, 0 <= k <= n^2. |
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+0
2
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| 1, 0, 1, 0, 0, 1, 1, 1, 0, 0, 0, 1, 2, 4, 3, 2, 1, 1, 0, 0, 0, 0, 1, 2, 8, 14, 21, 20, 20, 12, 9, 4, 2, 1, 1, 0, 0, 0, 0, 0, 1, 2, 10, 31, 76, 137, 221, 285, 321, 301, 253, 182, 122, 69, 38, 19, 10, 4, 2, 1, 1, 0, 0, 0, 0, 0, 0, 1, 2, 11, 43, 162, 451, 1121, 2314, 4255, 6702
(list; graph; listen)
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OFFSET
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0,13
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COMMENT
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The colors may be interchanged.
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REFERENCES
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R. W. Robinson, Numerical implementation of graph counting algorithms, AGRC Grant, Math. Dept., Univ. Newcastle, Australia, 1978.
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LINKS
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R. W. Robinson, Rows 0 through 7, flattened
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CROSSREFS
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Row sums give A122081. Cf. A007139, A106498 (gives beginning of this triangle).
Sequence in context: A011170 A109158 A049245 this_sequence A123551 A029717 A135567
Adjacent sequences: A123544 A123545 A123546 this_sequence A123548 A123549 A123550
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KEYWORD
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nonn,tabf
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com), Nov 14 2006
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