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Search: id:A159847
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| A159847 |
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The number of non-isomorphic n-node graphs with the maximal number of edges, and containing no three-cycles or four-cycles. |
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+0
1
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| 1, 1, 1, 2, 1, 2, 1, 1, 1, 1, 3, 7, 1, 4, 1, 22, 14, 15, 1, 1, 3
(list; graph; listen)
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OFFSET
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1,4
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COMMENT
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The Moore graphs are unique examples of these graphs for their orders. Thus the fiftieth term in this sequence is 1.
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REFERENCES
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D. K. Garnick and N. A. Nieuwejaar, Non-isomorphic Extremal Graphs without Three-Cycles or Four-Cycles, Journal of Combinatorial Mathematics and Combinatorial Computing, 12(1992), 33-56.
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CROSSREFS
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A006856
Sequence in context: A048138 A165022 A030338 this_sequence A106345 A081729 A080215
Adjacent sequences: A159844 A159845 A159846 this_sequence A159848 A159849 A159850
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KEYWORD
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hard,nonn
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AUTHOR
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David Garnick (dgarnick(AT)gmail.com), Apr 23 2009
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