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Search: id:A101204
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| A101204 |
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Triangle read by rows: T(n,k) = number of planar trivalent (or cubic) multigraphs with 2n nodes and exactly k double bonds, for 0 <= k <= n. |
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+0
3
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| 1, 0, 1, 1, 0, 1, 1, 1, 2, 1, 3, 4, 5, 4, 1, 9, 16, 22, 16, 7, 1, 32, 75, 112, 86, 41, 10, 1, 133
(list; table; graph; listen)
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OFFSET
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0,9
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COMMENT
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The entries in the first two rows are "by convention".
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REFERENCES
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A. T. Balaban, Enumeration of Cyclic Graphs, pp. 63-105 of A. T. Balaban, ed., Chemical Applications of Graph Theory, Ac. Press, 1976; see p. 92.
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EXAMPLE
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Triangle begins
1
0 1
1 0 1
1 1 2 1
3 4 5 4 1
9 16 22 16 7 1
32 75 112 86 41 10 1
133 ...
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CROSSREFS
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Row sums give A005966. First column is A005964 (trivalent connected planar graphs with 2n nodes). Second and third columns give A101205, A101206.
Sequence in context: A088267 A117407 A082470 this_sequence A035043 A155963 A058684
Adjacent sequences: A101201 A101202 A101203 this_sequence A101205 A101206 A101207
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KEYWORD
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nonn,tabl
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com), Dec 13 2004
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