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 A316522 Number of unlabeled rooted trees with n nodes where all terminal rooted subtrees are either constant or strict. 0
 1, 1, 2, 4, 8, 15, 34, 71, 165, 381, 913, 2193, 5389, 13287, 33155, 83196, 210251, 533956, 1363146, 3494266, 8993164, 23225281 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS EXAMPLE The a(6) = 15 rooted trees:   (((((o)))))   ((((oo))))   (((o(o))))   (((ooo)))   ((o((o))))   ((o(oo)))   (((o)(o)))   ((oooo))   (o(((o))))   (o((oo)))   (o(o(o)))   (o(ooo))   ((o)((o)))   ((o)(oo))   (ooooo) Missing from this list are:   ((oo(o)))   (oo((o)))   (oo(oo))   (o(o)(o))   (ooo(o)) MATHEMATICA Clear[strut]; strut[n_]:=strut[n]=If[n==1, {{}}, Select[Join@@Function[c, Union[Sort/@Tuples[strut/@c]]]/@IntegerPartitions[n-1], Or[SameQ@@#, UnsameQ@@#]&]]; Table[Length[strut[n]], {n, 15}] CROSSREFS Cf. A000081, A003238, A004111, A214577, A276625, A316521. Sequence in context: A061030 A036661 A145671 * A317712 A108693 A026096 Adjacent sequences:  A316519 A316520 A316521 * A316523 A316524 A316525 KEYWORD nonn,more AUTHOR Gus Wiseman, Jul 05 2018 EXTENSIONS a(16)-a(22) from Robert Price, Sep 16 2018 STATUS approved

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Last modified August 4 08:30 EDT 2021. Contains 346445 sequences. (Running on oeis4.)