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A331113
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Number of signed trees with n positive edges and n negative edges.
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3
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1, 1, 9, 96, 1439, 24758, 476056, 9841611, 214997756, 4900190330, 115530636036, 2800145556058, 69446136484047, 1756114394736162, 45152546920446518, 1177790435393100588, 31111743336031473800, 831007304851753985293, 22416683345590695488558, 610057933331757664054671
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listen;
history;
text;
internal format)
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OFFSET
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0,3
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COMMENTS
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The total number of nodes is 2n + 1. Trees are unrooted.
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LINKS
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FORMULA
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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