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A304068
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Number of trees on n vertices rooted at an oriented non-edge.
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2
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0, 0, 1, 4, 14, 45, 140, 424, 1269, 3760, 11080, 32517, 95190, 278154, 811887, 2367973, 6903453, 20120905, 58639016, 170894228, 498084608, 1451899005, 4232957241, 12343454790, 36001675800, 105028397290, 306472665459, 894497511566
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OFFSET
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1,4
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LINKS
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FORMULA
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EXAMPLE
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a(4)=4 is based on the same examples as in A304067, but the oriented edge that spans a leaf with the node at distance 2 in the linear graph may have 2 orientations, so a(4) is one larger than A304067(4).
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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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