Triangle read by rows: T(n,k) is the number of k-trees with n unlabeled nodes rooted at a front.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =1a(6) =1a(7) =2a(8) =1a(9) =1a(10) =1a(11) =4a(12) =2a(13) =1a(14) =1a(15) =1a(16) =9a(17) =6a(18) =2a(19) =1a(20) =1a(21) =1a(22) =20a(23) =21a(24) =6a(25) =2a(26) =1a(27) =1a(28) =1a(29) =48