|
%I #8 Jul 26 2022 14:35:06
%S 1,0,0,1,4,13,42,139,470,1616,5632,19852,70654,253559,916558,3334211,
%T 12197142,44842184,165597008,613991206,2284809072,8530458154,
%U 31945128628,119960276246,451621453764,1704240175868,6445111657272
%N Number of ordered trees with n edges and having no root-to-leaf branches.
%F a(n) = 2*sum((-1)^j*(j+2)*C(2n-3-2j,n), j=0..floor((n-3)/2))/(n+1).
%F G.f.: 2(1-z)/[1+z+(1-z)sqrt(1-4z)].
%F D-finite with recurrence +2*(n+1)*a(n) +6*(-2*n+1)*a(n-1) +(19*n-35)*a(n-2) +(-13*n+32)*a(n-3) +2*(2*n-7)*a(n-4)=0. - _R. J. Mathar_, Jul 26 2022
%K nonn
%O 0,5
%A _Emeric Deutsch_, May 29 2003
|
