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A124157
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Maximal number of edges in a doubly linear graph with n nodes.
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1
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OFFSET
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1,3
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COMMENTS
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a(9) is known to be 34 or 35. I have put 35 here so as to distinguish this sequence from the triangular numbers. But the true value is (or was in 1997 at least) not known.
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REFERENCES
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L. W. Beineke, Biplanar graphs: a survey, Computers Math. Applic., 34 (1997), 1-8.
Hutchinson, Joan P.; Shermer, Thomas; and Vince, Andrew; On representations of some thickness-two graphs. Comput. Geom. 13 (1999), 161-171.
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LINKS
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Table of n, a(n) for n=1..9.
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FORMULA
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For n >= 10, 6n-20 <= a(n) <= 6n-18.
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CROSSREFS
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Sequence in context: A124158 A161208 A109444 * A033440 A067525 A130487
Adjacent sequences: A124154 A124155 A124156 * A124158 A124159 A124160
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KEYWORD
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nonn,more
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AUTHOR
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N. J. A. Sloane, Dec 02 2006
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STATUS
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approved
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