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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
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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; refs; listen; history; internal format)
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OFFSET
| 1,4
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COMMENTS
| 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
| 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
| A006856
Sequence in context: A048138 A165022 A030338 * A144477 A106345 A194636
Adjacent sequences: A159844 A159845 A159846 * A159848 A159849 A159850
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KEYWORD
| hard,nonn
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AUTHOR
| David Garnick (dgarnick(AT)gmail.com), Apr 23 2009
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