Triangle read by rows: T(n,k) is the number of ternary trees with n edges and having k vertices of outdegree 1 (n >= 0, k >= 0).
A120981
Triangle read by rows: T(n,k) is the number of ternary trees with n edges and having k vertices of outdegree 1 (n >= 0, k >= 0).
Terms
- a(0) =1a(1) =0a(2) =3a(3) =3a(4) =0a(5) =9a(6) =1a(7) =27a(8) =0a(9) =27a(10) =18a(11) =12a(12) =162a(13) =0a(14) =81a(15) =15a(16) =270a(17) =90a(18) =810a(19) =0a(20) =243a(21) =138a(22) =270a(23) =2430a(24) =540a(25) =3645a(26) =0a(27) =729a(28) =189a(29) =2898
External references
- oeis: A120981