Triangle read by rows: T(n,k) is the number of hill-free Dyck paths of semilength n and having length of first descent equal to k (1<=k<=n; n>=1). A hill in a Dyck path is a peak at level 1.

A118972

Triangle read by rows: T(n,k) is the number of hill-free Dyck paths of semilength n and having length of first descent equal to k (1<=k<=n; n>=1). A hill in a Dyck path is a peak at level 1.

Terms

    a(0) =0a(1) =0a(2) =1a(3) =1a(4) =0a(5) =1a(6) =3a(7) =2a(8) =0a(9) =1a(10) =10a(11) =5a(12) =2a(13) =0a(14) =1a(15) =33a(16) =16a(17) =5a(18) =2a(19) =0a(20) =1a(21) =111a(22) =51a(23) =16a(24) =5a(25) =2a(26) =0a(27) =1a(28) =379a(29) =168

External references