%I #9 Nov 05 2019 05:52:29
%S 1,2,4,8,16,32,65,134,280,598,1300,2884,6516,15008,35147,83680,202139,
%T 494982,1226753,3074146,7779561,19863702,51125018,132541616,345867101,
%U 907922596,2396276355,6355845398,16934718359,45309972502,121697068925,328029259192
%N Number of bicolored acyclic graphs on n unlabeled nodes.
%C The two color classes are not interchangeable. Adjacent nodes cannot have the same color.
%H Andrew Howroyd, <a href="/A329053/b329053.txt">Table of n, a(n) for n = 0..500</a>
%F Euler transform of A122086.
%o (PARI)
%o EulerT(v)={Vec(exp(x*Ser(dirmul(v,vector(#v,n,1/n))))-1, -#v)}
%o TreeGf(N)={my(A=vector(N, j, 1)); for (n=1, N-1, A[n+1] = 1/n * sum(k=1, n, sumdiv(k, d, d*A[d]) * A[n-k+1] ) ); x*Ser(A)}
%o seq(n)={concat([1], EulerT(Vec(2*TreeGf(n) - TreeGf(n)^2)))}
%Y Antidiagonal sums of A329052.
%Y Cf. A122086.
%K nonn
%O 0,2
%A _Andrew Howroyd_, Nov 02 2019