Triangle read by rows: T(n,k) is the number of ordered trees with n edges and k protected vertices (0<=k<=n-1). A protected vertex in an ordered tree is a vertex at least 2 edges away from its leaf descendants.
A143362
Triangle read by rows: T(n,k) is the number of ordered trees with n edges and k protected vertices (0<=k<=n-1). A protected vertex in an ordered tree is a vertex at least 2 edges away from its leaf descendants.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =3a(4) =1a(5) =1a(6) =6a(7) =6a(8) =1a(9) =1a(10) =17a(11) =13a(12) =10a(13) =1a(14) =1a(15) =43a(16) =50a(17) =22a(18) =15a(19) =1a(20) =1a(21) =123a(22) =141a(23) =109a(24) =33a(25) =21a(26) =1a(27) =1a(28) =343a(29) =481
External references
- oeis: A143362