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This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A330627 Number of non-isomorphic phylogenetic trees with n nodes.

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%I A330627 #8 Jan 02 2021 21:21:34
%S A330627 0,1,1,1,2,2,4,5,9,14,24,39,69,116,205,357,632,1118,2001,3576,6445,
%T A330627 11627,21080,38293,69819,127539,233644,428825,788832,1453589,2683602,
%U A330627 4962167,9190155,17044522,31655676,58866237,109600849,204293047,381212823,712073862
%N A330627 Number of non-isomorphic phylogenetic trees with n nodes.
%C A330627 A phylogenetic tree is a series-reduced rooted tree whose leaves are (usually disjoint) sets. Each branching as well as each element of each leaf contributes to the number of nodes.
%H A330627 Andrew Howroyd, <a href="/A330627/b330627.txt">Table of n, a(n) for n = 1..500</a>
%F A330627 G.f.: A(x) satisfies A(x) = x*(1/(1-x) - A(x) - 2 + exp(Sum_{k>0} A(x^k)/k)). - _Andrew Howroyd_, Jan 02 2021
%e A330627 Non-isomorphic representatives of the a(2) = 1 through a(9) = 9 trees (commas and outer brackets elided):
%e A330627   1  12  123  1234    12345    123456     1234567      12345678
%e A330627               (1)(2)  (1)(23)  (1)(234)   (1)(2345)    (1)(23456)
%e A330627                                (12)(34)   (12)(345)    (12)(3456)
%e A330627                                (1)(2)(3)  (1)(2)(34)   (123)(456)
%e A330627                                           (1)((2)(3))  (1)(2)(345)
%e A330627                                                        (1)(23)(45)
%e A330627                                                        (1)((2)(34))
%e A330627                                                        (1)(2)(3)(4)
%e A330627                                                        (12)((3)(4))
%o A330627 (PARI) EulerT(v)={Vec(exp(x*Ser(dirmul(v,vector(#v,n,1/n))))-1, -#v)}
%o A330627 seq(n)={my(v=[0]); for(n=1, n-1, v=concat(v, EulerT(v)[n] - v[n] + 1)); v} \\ _Andrew Howroyd_, Jan 02 2021
%Y A330627 Phylogenetic trees by number of labels are A005804, with unlabeled version A141268.
%Y A330627 Balanced phylogenetic trees are A320154.
%Y A330627 Cf. A000311, A000669, A001678, A004114, A005121, A007716, A048816, A060356, A330465, A330467, A330469.
%K A330627 nonn
%O A330627 1,5
%A A330627 _Gus Wiseman_, Dec 28 2019
%E A330627 Terms a(11) and beyond from _Andrew Howroyd_, Jan 02 2021