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 A081629 Number of 9-level labeled rooted trees with n leaves. 6
 1, 1, 9, 117, 1989, 41709, 1038975, 29947185, 979687005, 35839643175, 1449091813035, 64144495494825, 3084209792570721, 160023238477245789, 8909102551102555002, 529651263967161225648, 33482356679629151295651 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 REFERENCES J. Ginsburg, Iterated exponentials, Scripta Math., 11 (1945), 340-353. T. Hogg and B. A. Huberman, Attractors on finite sets: the dissipative dynamics of computing structures, Phys. Review A 32 (1985), 2338-2346. LINKS Alois P. Heinz, Table of n, a(n) for n = 0..150 FORMULA E.g.f.: exp(exp(exp(exp(exp(exp(exp(exp(exp(x)-1)-1)-1)-1)-1)-1)-1)-1). PROG (PARI) a(n)=local(X); if(n<0, 0, X=x+x*O(x^n); n!*polcoeff(exp(exp(exp(exp(exp(exp(exp(exp(exp(X)-1)-1)-1)-1)-1)-1)-1)-1), n)). CROSSREFS Cf. A000110, A000258, A000307, A000357, A001669. Column k=8 of A144150. Sequence in context: A294190 A113344 A305968 * A051617 A166823 A322928 Adjacent sequences:  A081626 A081627 A081628 * A081630 A081631 A081632 KEYWORD nonn AUTHOR Benoit Cloitre, Apr 23 2003 STATUS approved

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Last modified October 19 03:20 EDT 2019. Contains 328211 sequences. (Running on oeis4.)