Triangle read by rows: T(n,k) is the number of ternary trees with n edges and having k middle edges (n >= 0, k >= 0).
A120986
Triangle read by rows: T(n,k) is the number of ternary trees with n edges and having k middle edges (n >= 0, k >= 0).
Terms
- a(0) =1a(1) =2a(2) =1a(3) =5a(4) =6a(5) =1a(6) =14a(7) =28a(8) =12a(9) =1a(10) =42a(11) =120a(12) =90a(13) =20a(14) =1a(15) =132a(16) =495a(17) =550a(18) =220a(19) =30a(20) =1a(21) =429a(22) =2002a(23) =3003a(24) =1820a(25) =455a(26) =42a(27) =1a(28) =1430a(29) =8008
External references
- oeis: A120986