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A339787 Number of homeomorphically irreducible leaf colored trees with n leaves using exactly 4 colors.

%I A339787 #8 Jan 10 2021 02:13:45
%S A339787 0,0,0,4,68,812,8512,84312,814184,7781712,74182124,708344640,
%T A339787 6790655496,65440865012,634347822304,6186652422650,60707391493004,
%U A339787 599283097168488,5950282272766412,59408426130151164,596269843123151304,6014472189177940224,60952019560703982452
%N A339787 Number of homeomorphically irreducible leaf colored trees with n leaves using exactly 4 colors.
%H A339787 Andrew Howroyd, <a href="/A339787/b339787.txt">Table of n, a(n) for n = 1..500</a>
%e A339787 There are 2 homeomorphically reduced trees with 4 leafs:
%e A339787             o          o   o
%e A339787             |          |   |
%e A339787         o---o---o      o---o
%e A339787             |          |   |
%e A339787             o          o   o
%e A339787 The leaves of the first tree can be colored in 1 way using all four colors and the second can be colored in 3 ways, so a(4) = 1 + 3 = 4.
%o A339787 (PARI) my(N=25); M(N,4)[2..1+N, 5]~ \\ See A339780 for M(n, m).
%Y A339787 Column k=4 of A339780.
%Y A339787 Cf. A339785, A339786.
%K A339787 nonn
%O A339787 1,4
%A A339787 _Andrew Howroyd_, Dec 18 2020