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A330465 Number of non-isomorphic series-reduced rooted trees whose leaves are multisets with a total of n elements. 19

%I #12 Dec 14 2020 01:37:10

%S 1,4,14,87,608,5573,57876,687938,9058892,130851823,2048654450,

%T 34488422057,620046639452,11839393796270,238984150459124,

%U 5079583100918338,113299159314626360,2644085918303683758,64393240540265515110,1632731130253043991252,43013015553755764179000

%N Number of non-isomorphic series-reduced rooted trees whose leaves are multisets with a total of n elements.

%C Also inequivalent leaf-colorings of phylogenetic rooted trees with n labels. A phylogenetic rooted tree is a series-reduced rooted tree whose leaves are (usually disjoint) sets.

%e Non-isomorphic representatives of the a(3) = 14 trees:

%e ((1)((1)(1))) ((1)((1)(2))) ((1)((2)(3))) ((2)((1)(1)))

%e ((1)(1)(1)) ((1)(1)(2)) ((1)(2)(3)) ((2)(1,1))

%e ((1)(1,1)) ((1)(1,2)) ((1)(2,3))

%e (1,1,1) (1,1,2) (1,2,3)

%o (PARI) \\ See links in A339645 for combinatorial species functions.

%o cycleIndexSeries(n)={my(v=vector(n), p=sEulerT(x*sv(1) + O(x*x^n))); v[1]=sv(1); for(n=2, #v, v[n] = polcoef( sEulerT(x*Ser(v[1..n])), n ) + polcoef(p,n)); x*Ser(v)}

%o InequivalentColoringsSeq(cycleIndexSeries(15)) \\ _Andrew Howroyd_, Dec 13 2020

%Y The version where leaves are atoms is A318231.

%Y The case with sets as leaves is A330624.

%Y The case with disjoint sets as leaves is A141268.

%Y Labeled versions are A330467 (strongly normal) and A330469 (normal).

%Y The singleton-reduced version is A330470.

%Y Cf. A000311, A000669, A004114, A005804, A007716, A281118, A289501, A292504, A316651, A316652, A318812, A319312, A330471, A330474, A330625, A339645.

%K nonn

%O 1,2

%A _Gus Wiseman_, Dec 21 2019

%E Terms a(7) and beyond from _Andrew Howroyd_, Dec 13 2020

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Last modified March 18 22:56 EDT 2024. Contains 370952 sequences. (Running on oeis4.)