Triangle read by rows: R*(n,k) (n>=2, k from 2 to n-1 or to 2 if n = 2), where R*(n,k) = number of trees with n nodes and k unlabeled end-nodes.

A213262

Triangle read by rows: R*(n,k) (n>=2, k from 2 to n-1 or to 2 if n = 2), where R*(n,k) = number of trees with n nodes and k unlabeled end-nodes.

Terms

    a(0) =1a(1) =1a(2) =1a(3) =1a(4) =3a(5) =2a(6) =1a(7) =12a(8) =9a(9) =3a(10) =1a(11) =60a(12) =52a(13) =18a(14) =4a(15) =1a(16) =360a(17) =360a(18) =136a(19) =30a(20) =5a(21) =1a(22) =2520a(23) =2880a(24) =1205a(25) =280a(26) =45a(27) =6a(28) =1a(29) =20160

External references