Triangular array read by rows. T(n,k) is the number of rooted labeled trees on n nodes with exactly k vertices whose unique descendent is a leaf, n >= 1, 0 <= k <= floor((n-1)/2) + delta_{2,n}.

A284417

Triangular array read by rows. T(n,k) is the number of rooted labeled trees on n nodes with exactly k vertices whose unique descendent is a leaf, n >= 1, 0 <= k <= floor((n-1)/2) + delta_{2,n}.

Terms

    a(0) =1a(1) =0a(2) =2a(3) =3a(4) =6a(5) =16a(6) =48a(7) =145a(8) =420a(9) =60a(10) =1536a(11) =4800a(12) =1440a(13) =19579a(14) =65730a(15) =31500a(16) =840a(17) =290816a(18) =1053696a(19) =698880a(20) =53760a(21) =4942305a(22) =19332936a(23) =16367400a(24) =2388960a(25) =15120a(26) =94689280a(27) =399052800a(28) =410296320a(29) =93542400

External references