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A277863
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Number of connected, unlabeled, unrooted 3-leaf power graphs on n vertices.
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0
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1, 1, 2, 5, 12, 32, 82, 227, 629, 1840, 5456, 16701, 51939, 164688, 529070, 1722271, 5664786, 18813360, 62996841, 212533216, 721792751, 2466135364, 8471967927, 29249059281, 101440962284, 353289339914, 1235154230047, 4333718587339, 15255879756019, 53870521140911
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OFFSET
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0,3
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COMMENTS
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a(n) is the number of unlabeled and unrooted distance-hereditary graphs on n vertices; the enumeration is obtained from the symbolic specification / generating functions through Maple's combstruct library--an arbitrary number of terms can be derived.
Enumeration also exists in various other configurations of unlabeled/labeled, unrooted/rooted, etc.
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LINKS
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CROSSREFS
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Subset of A277862 (distance-hereditary graphs).
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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