This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A055334 #10 Mar 30 2012 17:37:10 %S A055334 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 A055334 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 A055334 69,1,0,0,14,127,445,591,276,27,0,0,16,173,739,1273,868,172,3,0,0,19 %N A055334 Number of asymmetric (identity) trees with n nodes and k leaves. %C A055334 A pair of zeros marks the next row. %H A055334 <a href="/index/Tra#trees">Index entries for sequences related to trees</a> %F A055334 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 A055334 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 A055334 Row sums give A000220. Columns 3 through 8: A001399(n-7), A055335-A055339. %K A055334 nonn,tabf %O A055334 1,15 %A A055334 _Christian G. Bower_, May 12 2000