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 A316500 Number of unlabeled rooted identity trees with n nodes in which the branches of any node with more than one branch have empty intersection. 6
 1, 1, 1, 2, 3, 6, 11, 22, 46, 96, 205, 442, 976, 2146, 4789, 10719, 24202, 54841, 124967, 285724, 656011, 1510929, 3491151, 8088692, 18790084 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 LINKS EXAMPLE The a(7) = 11 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@@#&&Or[Length[#]==1, Intersection@@#=={}]&]]; Table[Length[strut[n]], {n, 20}] CROSSREFS Cf. A000081, A004111, A007562, A078374, A289509, A316469, A316471, A316474, A316501, A316503. Sequence in context: A096202 A036653 A318031 * A123769 A093304 A036590 Adjacent sequences: A316497 A316498 A316499 * A316501 A316502 A316503 KEYWORD nonn,more AUTHOR Gus Wiseman, Jul 05 2018 STATUS approved

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Last modified January 30 22:45 EST 2023. Contains 359947 sequences. (Running on oeis4.)