Search: id:A003228 Results 1-1 of 1 results found. %I A003228 M0351 %S A003228 1,2,2,5,9,21,43,101,226,556,1333,3365,8500,22007,57258,151264,401761, %T A003228 1077063,2902599,7871250,21440642,58672589,161155637,444240627, %U A003228 1228400744,3406668865,9472308269,26402207803,73755064178 %N A003228 Endpoints in trees with n nodes. %D A003228 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %D A003228 R. W. Robinson and A. J. Schwenk, The distribution of trees in a large random tree, Discr. Math., 12 (1975), 359-. %H A003228 Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics. %H A003228 Index entries for sequences related to trees %F A003228 a(n)=sum{k=1 to n} k*c(n, k), where c(n, k) = A055290(n, k) has g.f. (1-x+x*y)*B(x, y)+(1/2)*(B(x^2, y^2)-B(x, y)^2) and B(x, y) is g.f. for A055372. %Y A003228 Cf. A000055, A003227, A055290. %Y A003228 Sequence in context: A052969 A002990 A060405 this_sequence A110182 A075125 A081374 %Y A003228 Adjacent sequences: A003225 A003226 A003227 this_sequence A003229 A003230 A003231 %K A003228 nonn %O A003228 1,2 %A A003228 N. J. A. Sloane (njas(AT)research.att.com). %E A003228 Corrected and extended with formula by Christian G. Bower (bowerc(AT)usa.net), May 25 2000 Search completed in 0.001 seconds