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A316473
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Number of locally disjoint rooted trees with n nodes, meaning no branch overlaps any other (unequal) branch of the same root.
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29
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1, 1, 2, 4, 9, 19, 44, 99, 233, 554, 1346, 3300, 8219, 20635, 52300, 133488, 343033, 886360, 2302133, 6005835
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OFFSET
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1,3
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LINKS
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EXAMPLE
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The a(5) = 9 locally disjoint rooted trees:
((((o))))
(((oo)))
((o(o)))
((ooo))
(o((o)))
(o(oo))
((o)(o))
(oo(o))
(oooo)
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MATHEMATICA
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strut[n_]:=strut[n]=If[n===1, {{}}, Select[Join@@Function[c, Union[Sort/@Tuples[strut/@c]]]/@IntegerPartitions[n-1], Select[Tuples[#, 2], UnsameQ@@#&&(Intersection@@#=!={})&]=={}&]];
Table[Length[strut[n]], {n, 15}]
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CROSSREFS
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KEYWORD
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nonn,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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