Triangle read by rows: T(n,k) is number of hex trees with n edges and k vertices of outdegree 1 (0<=k<=n).

A126178

Triangle read by rows: T(n,k) is number of hex trees with n edges and k vertices of outdegree 1 (0<=k<=n).

Terms

    a(0) =1a(1) =0a(2) =3a(3) =1a(4) =0a(5) =9a(6) =0a(7) =9a(8) =0a(9) =27a(10) =2a(11) =0a(12) =54a(13) =0a(14) =81a(15) =0a(16) =30a(17) =0a(18) =270a(19) =0a(20) =243a(21) =5a(22) =0a(23) =270a(24) =0a(25) =1215a(26) =0a(27) =729a(28) =0a(29) =105

External references