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 A316471 Number of locally disjoint rooted identity trees with n nodes, meaning no branch overlaps any other branch of the same root. 20
 1, 1, 1, 2, 3, 6, 11, 21, 43, 89, 185, 391, 840, 1822, 3975, 8727, 19280, 42841, 95661, 214490 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 LINKS EXAMPLE The a(7) = 11 locally disjoint rooted identity trees: ((((((o)))))) ((((o(o))))) (((o((o))))) ((o(((o))))) ((o(o(o)))) (((o)((o)))) (o((((o))))) (o((o(o)))) (o(o((o)))) ((o)(((o)))) (o(o)((o))) MATHEMATICA strut[n_]:=strut[n]=If[n===1, {{}}, Select[Join@@Function[c, Union[Sort/@Tuples[strut/@c]]]/@IntegerPartitions[n-1], UnsameQ@@#&&Select[Tuples[#, 2], UnsameQ@@#&&(Intersection@@#=!={})&]=={}&]]; Table[Length[strut[n]], {n, 20}] CROSSREFS Cf. A000081, A004111, A276625, A277098, A302696, A303362, A304713, A316467, A316471, A316473, A316474, A316494. Sequence in context: A164362 A329667 A026742 * A018268 A082616 A018613 Adjacent sequences:  A316468 A316469 A316470 * A316472 A316473 A316474 KEYWORD nonn,more AUTHOR Gus Wiseman, Jul 04 2018 STATUS approved

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Last modified November 28 13:47 EST 2021. Contains 349413 sequences. (Running on oeis4.)