

A055334


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


6



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

1,15


COMMENTS

A pair of zeros marks the next row.


LINKS

Table of n, a(n) for n=1..80.
Index entries for sequences related to trees


FORMULA

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


EXAMPLE

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; ...


CROSSREFS

Row sums give A000220. Columns 3 through 8: A001399(n7), A055335A055339.
Sequence in context: A290255 A283982 A173402 * A106237 A071675 A221833
Adjacent sequences: A055331 A055332 A055333 * A055335 A055336 A055337


KEYWORD

nonn,tabf


AUTHOR

Christian G. Bower, May 12 2000


STATUS

approved



