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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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2
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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, 3, 7, 1, 6, 2, 1, 4, 1, 1, 2, 1
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OFFSET
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1,4
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COMMENTS
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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.
Two additional values of this sequence determined: a(24)=1 and a(32)=1. [Michael Codish, Apr 09 2013]
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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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LINKS
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CROSSREFS
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KEYWORD
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nonn,hard,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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