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A055334 Number of asymmetric (identity) trees with n nodes and k leaves. 6


%S 1,0,0,0,0,0,0,0,1,0,0,1,0,0,2,1,0,0,3,3,0,0,0,4,8,3,0,0,5,14,10,0,0,

%T 0,7,25,29,6,0,0,8,40,65,25,1,0,0,10,62,135,90,13,0,0,12,89,252,244,

%U 69,1,0,0,14,127,445,591,276,27,0,0,16,173,739,1273,868,172,3,0,0,19

%N Number of asymmetric (identity) trees with n nodes and k leaves.

%C A pair of zeros marks the next row.

%H <a href="/index/Tra#trees">Index entries for sequences related to trees</a>

%F G.f.: A(x, y)=(1-x+x*y)*B(x, y)-(1/2)*(B(x, y)^2+B(x^2, y^2)). B(x, y): g.f. of A055327.

%e 1; 0; 0; 0; 0; 0; 0,0,1; 0,0,1; 0,0,2,1; 0,0,3,3; 0,0,4,8,3; ...

%Y Row sums give A000220. Columns 3 through 8: A001399(n-7), A055335-A055339.

%K nonn,tabf

%O 1,15

%A _Christian G. Bower_, May 12 2000

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Last modified January 18 16:27 EST 2020. Contains 331011 sequences. (Running on oeis4.)