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 A220818 Number of rooted binary MUL-trees with n leaves on the label set [5]. 2
 5, 15, 75, 495, 3600, 28275, 232500, 1979385, 17287050, 154041450, 1394844375, 12797919900, 118722187125, 1111672312125, 10493033896875, 99734572903680, 953755379940150, 9169941599036475, 88588446263805000, 859511126918229075, 8371534717621838250 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Andrew Howroyd, Table of n, a(n) for n = 1..200 V. P. Johnson, Enumeration Results on Leaf Labeled Trees, Ph. D. Dissertation, Univ. Southern Calif., 2012. MATHEMATICA a[n_] := a[n] = If[n < 2, 5 n, If[OddQ[n], 0, (# (1 - #)/2 &)[a[n/2]]] + Sum[a[i] a[n - i], {i, 1, n/2}]]; Array[a, 25] (* Jean-François Alcover, Sep 02 2019, after Alois P. Heinz in A319539 *) CROSSREFS Column 5 of A319539. Sequence in context: A149654 A149655 A032122 * A064678 A088935 A183937 Adjacent sequences:  A220815 A220816 A220817 * A220819 A220820 A220821 KEYWORD nonn AUTHOR N. J. A. Sloane, Dec 22 2012 EXTENSIONS Terms a(11) and beyond from Andrew Howroyd, Sep 23 2018 STATUS approved

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Last modified September 25 04:45 EDT 2021. Contains 347652 sequences. (Running on oeis4.)